Just an anecdote: I decided to learn button accordion. The accordion I first got required an overhaul and the accordion builder around here said it would take half a year. So I looked for some reasonably affordable and comparable substitute and found that there was a "Morino, similar to Artiste VI" on offer in Switzerland on a sale for something like EUR500. Can't do wrong much with that. Pictures looked suspicious: quite unusual controls, but the instrument was supposed to be playable. It wasn't really: the bass section was probably lubricated with some sort of oil (which is a terrible idea to start with and becomes worse as the oil gets old). So I spent a multiple of the starting cost with more than one different accordion makers to get the instrument in working condition.
Still quite cheaper than a new instrument. And I've been playing it since then. Turns out this "cheap" instrument intended for temporary use was likely built for a renowned soloist in 1960 (his name is part of the mechanics inside), probably to convince him to try playing a more customary single-note bass system than the one-of-a-kind system he was playing at the time (he was good enough that Hohner never had him pay for any instrument). There is no evidence of him ever playing this instrument.
But it was a pretty good pitch. The bass system likely having scared most buyers away allows for 168 different registrations which are, astonishingly, pretty much all workable for some purpose. I have test-played some high-end new instruments for interest, expecting to come to the "well, if one ever had the money, this would be nice to have instead" conclusion.
But I was wrong about that. Yes, the mechanics are quieter, the instruments are less heavy. But you play a large crescendo, and the sound is like turning a volume control. And it's not like the volume control on the bass and the treble section have the same characteristic.
With my old instrument, it is more like a drama control. The sound unfurls, like a bowed string instrument. And except for some outlandish registrations (like 10-reed bass on single-reed treble...), you get musically useful results.
To get back on-topic: playing this kind of instrument makes it reasonably straightforward to see how you can be better. It provides positive feedback rather easily. And yes, it teaches you some things that you then know to look for and get to some approximation from cheaper instruments. There is a reason that music conventions hire some of the best players to sell mediocre instruments: those players know what they want to get from instruments, and they are good at fighting the instrument until they get it.
But as a beginner, you are not able to fight an instrument. An instrument outclassing you will not make you a good player. But it makes it easier for you to recognize when and how you improve, and makes the way more rewarding.