Ritonmousquetaire, you wrote:
"But beginners might want to achieve what they have in mind, and therefore imagine better-suited instruments - it's not necessarily bad, imho. But it may be a sign that they should have a look at other instruments that will allow them to play what they want."
To me, this makes a lot more sense than your thread title "Can you play concertina like accordion?"
A beginner can have one of two differnt starting points: either he comes into contact with a particular instrument and wants to play it like the players he has heard; or he comes into contact with a particular genre of music, and looks for an instrument that will serve him in this.
In real life, instruments and musical genres are meshed. The violoncello is almost exclusively meshed with classical music; the Anglo concertina almost exclusively with British and Irish folk music. The violin and accordion, by contrast, are associated with classical music, jazz and the folk musics of many countries.
Looking at it from the other side, classical music is meshed with many instruments - piano, strings, woodwind, brass - but not with the Anglo concertina. Similarly, modern Irish dance music is meshed with uileann pipes, fiddle, flute, whistles, Anglo concertina, tenor banjo, bouzouki, bodhran - and that's about it. No saxes, trumpets or clarinets.
It seems to me, Ritonmousquetaire, that you are the type of beginner who has identified the genre of music he's aiming for, and should be looking for an instrument that will serve the purpose. If accordion capability is a criterion for you, why not learn the accordion? Or at least some instrument that is meshed with several different genres, since you don't seem to be the dedicated, folkie, jazzman or classical musician.
Or you can do it like I have - learn several different instruments, and use the one that best transports your current musical ideas. There are so many different instruments out there, and each of them has the rich history of experience and inventiveness behind them that Mikefule rightly mentions. No need to re-invent the wheel - just choose the one that suits you and is already tried and tested.
(It was Accordian who started the thread, not Ritonmousquetaire.)
That aside, I like your different perspective on the same issue. Where I said, "This is what the Anglo does or doesn't do, work with it," you said, "This is what you want to play, then find an instrument that will work with it." I agree.
Because of my passion for the Anglo, I felt the need both to advocate it and defend it and lost sight of the other side of the discussion.
However, I fully appreciate the problem of wanting to play one type of music and wanting to play an instrument that doesn't suit it. I play English/Morris tunes and odds and ends of other mainly folk styles on the Anglo, but when I listen to recorded music it is usually rockabilly and the genres each side of it: country, blues, and rock. Every so often I try my best, but I just can't get that twangy sound on the Anglo!