> having a cheap, but not-great equipment is a good stepping stone.
I don't agree for something like this. The problem is that beginners often don't understand how to deal with the limitations of equipment--all they understand is that something is wonky and they don't know how to fix it.
In addition, bad equipment can make your initial impressions so painful that they prevent you from going further. Oscilloscopes, cheap soldering tools, etc. all have this effect. It's not unique to electrical engineering though--super cheap guitars are painful to play while something just $150 more is dramatically easier to deal with.
Where cheap equipment shines is when a beginner has been at it long enough and becomes "dangerous". They know just enough to do things but not enough to avoid things that will destroy their equipment. That's when the $20 "whatever" is a blessing because you'll get annoyed but you won't be distraught if you blow it up. Even as someone experienced, I semi-regularly destroy a $10 logic analyzer because the circuit I was analyzing wasn't doing what I thought it was (of course, this is mostly laziness--since the analyzer is merely $10 I don't take the time to double check things that I would if I were to put my Agilent analyzer on it)
> Besides, beginners won't have the skill to fully use fully-featured pro-level-gear.
Quite often, pro gear is better for beginners. For a beginner, an "Auto Scale" button on their scope that does the right thing is a godsend. Even I use it all the time. Sure, I can dial the signals in quickly, but "Auto Scale" does the right thing 99% of the time with a single button press.
Even with soldering, a Metcal system maintains the temperature exactly where you need it. You don't have to worry about having too much/not enough heat on the component you are working with. You don't have to worry about the calibration on your soldering station. A Metcal will pump a lot more energy into a big hunk of transformer and a lot less energy into a QFP integrated circuit. Sure, someone experienced can adjust for this on a Hakko, but a beginner is having a tough enough time getting solder down and the soldering iron in the right place without knocking the IC all over the place and doing it all through a microscope.
> investing in an expensive soldering station is wasteful if one decides that it's not really for them.
Used Metcal soldering systems are "expensive" ($250-$500), but they also resell for almost the exact same amount you bought them. Cheap soldering stations won't resell for anything. So, all the money you spend on a cheap station is lost if you decide not to go further while the expensive station cost all gets recovered.