I mean this in the kindest possible way while still being critical: I really wish people would stop making definitive statements about things that, I'm sorry to say, they don't understand. This is just wrong. The end result is absolutely not the same, for multiple reasons:
1. Decisions by consular officials largely can't be challenged (with some exceptions). Decisions by USCIS can be challenged in immigration court and/or federal court, depending on your case;
2. Thanks to Trump v. Hawaii, the president has the broad power to ban the granting of visas to people overseas. There's currently a ban on 39 countries. That cannot be challenged. It can be challenged in the US;
3. When you apply for an immigration benefit in the US, the USCIS field office that deals with it is determined by where you live. It used to be the case that if you were outside the US, you could get an embassy appointment in the country you were residing in. This administration changed that such that you can only use the embassy in your country of birth/citizenship. So, if you're a Kenyan citizen living and working in France, you have to go back to Kenya for your consular interview. That might take wait times for getting an interview from 1-2 months to 1-2 years, depending on the embassy. It's also a huge hassle and expensive, possibly;
4. The GP is correct here. When you apply for any immigrant visa, meaning you or a spouse, sibling, parent, child or employer files an I130/I140 for you, you've demonstrated what's called "immigrant intent". That means that for people from many countries they are unlikely to ever get a nonimmigrant visa ever again. USCIS thinks you're tryign to sneak into the US to adjust status rather than consular processing. They also think if you enter the US, you won't leave. Obviously citizens of Norway are treated differently to citizens of Nigeria. I'll let you ponder why;
5. If you accrue unlawful presence in the US (for which the rules are complicated), you may get a 3 or 10 year bar on returning to the US. In addition, because you have overstayed a visa (or have entered without inspection), you may simply not ever get another visa again anyway. It's unclear from this memo if the 3/10 year bars will apply here. We won't know until we see how it's implemented;
6. Certain people may be in limbo because they don't have the option to leave to consular process. I'm mainly thinking of people who have made an asylum claim. There are people who have filed for asylum in 2015 who don't have a ruling on that case yet. 11 years is a long time. They might meet someone and get married and then seek to adjust. This is a complicated process that comes with its own perils but generally they adjust status and then withdraw their asylum case or, in some cases, seek cancellation of removal from immigration court. Do they have to leave? They may not have travel documents. They can't really go back to their home country. This may create a situation where they can't adjust and they can't leave so they're in limbo. Also, if the asylum office decides your asylum case was "frivolous", you may have a permanent bar on ever receiving an immigration benefit. That's much more difficult if not impossible to challenge overseas;
7. What makes you inadmissibile isn't necessarily serious. It can be a simple mistake. For example, if you marry a US citizen then working without authorization is forgiven (mostly; it's complicated) but you have to be really careful how you answer questions on the forms and to officers. So you might answer "no" the I485 question about working without authorization even though you did a few Ubers 7 years ago, which is forgiven, but you've now made a false claim and that may make you inadmissible needing a waiver. A good lawyer will argue that it wasn't "material" but this USCIS much more than any previouis is having a stricter interpretation of any of this;
8. As another example, "crimes", particularly "aggravated" crimes or crimes of "moral terpitude" can make you inadmissible. But what are those? There are guidelines but there's some grey areas where USCIS has discretion. For example, being convicted of a crime with a potential sentence of more than 365 days will make you inadmissible. But sentencing guidelines can be whack such that if you speed as a 16 year old, you might get charged with something and, not knowing any better, get offered a deal for probation on a crime of reckless driving that can technically be up to 2 years of jail time by the sentencing guidelines. Well, guess what? You're now guilty of an aggravated crime and can not only have your green card denied, you can be denaturalized and deported. No, this isn't a made up example.
IANAL but I know what I know and, more importantly, I know what I don't know, which is a lot. But what's particularly frustrating to me is the people who have no idea what they don't know. The above just scratches the surface.