Yes, if you do a lot of business communication, this stuff is important. I talk to way too many people that should know better that clearly don't have a clue about any of this and that end up looking and sounding pretty poorly
It's pretty simple. Most bluetooth headsets are not great, including the expensive ones that Apple sells you. And even if they are good, the bluetooth audio compression is pretty bad. So, you are unlikely to sound very clear. So, avoid that and use wired headsets or even your laptop's build in microphone instead. For optimal results, invest in a good microphone. There's a reason professional podcast hosts sound so good: they use proper microphones. You can sound that good as well. A simple, wired clip on microphone doesn't cost a fortune.
Audio filtering is pretty aggressive these days and that can cause additional issues. For example eliminating feedback and echoes is something that a lot of software tries that can result in your audio cutting out and getting distorted. Solution: wear headphones to listen to the sound. This prevents feedback from having to be filtered out. Also, being in a quiet environment helps.
As the article notes, many webcams are not great in terms of hardware. In practical terms this means low resolution sensors that will have a lot of noise. The darker it gets, the worse it gets. So be in a well lit room and pay some attention to the light situation. A simple desk light turned the right way can do wonders at night. Professional youtubers tend to invest in special lights for a reason: it makes things look good.
Obviously, you need a stable network connection. Doing multiple video calls on a domestic wifi that has multiple family members doing whatever in a room that is around 10 meters from the base station is probably going to result in a pretty bad connection. A few meters can make all the difference. And if you are upload constrained (like many DSL connections are), there are going to be issues. If it's really bad, turn off your video. You'll sound better that way and people will be able to understand you at least.
Finally, pay attention to where the camera is pointing. If you are a sales person that spends a lot of money on their outfit, do you really want the lasting impression to make to be your nostrils filmed from below? Also, clean the room you are in and don't have a backdrop of your domestic crap, laundry, and worse. It just does not look professional to do that. It's not hard but you need to pay some attention. If it's really bad, you can use a fake backdrop or blur it. But be aware that that can look a bit glitchy on the other side. Better to just be in a nice looking place. Also nice for yourself BTW.