It opened up a whole new world of music for me.
I played violin for more than 3 decades, but in that time, I don't remember ever learning to play a piece just for fun. I played in quartets and orchestras, playing music somebody else chose, and I played insanely hard etudes, I had no energy left over to play even more after that, and had no love for the sound of my own playing, only for how the orchestra sounded together. I sure as hell didn't listen to very many solo violin recordings for fun.
I bought an accordion because I was in an ensemble that was all treble instruments and we needed someone who could play the cello parts. The ensemble fell apart before my accordion arrived in the mail.
And then - wow!
For the first time I could play complete pieces of music, melody and chords together rather than a single line. I could play anything I wanted, subject to the limits of my ability. I had to, or got to, think about how to organize a mini-concert program. I could think about busking. I could play just to make myself happy.
Practicing is actually fun. Sure there are frustrating days... but I can hear myself sounding better with time, I can enjoy listening to recordings of others playing my instrument, I can go to accordion festivals. (There are lots of classical music festivals -- mostly exclusive and expensive, either to play or to watch, but not 'violin festivals' outside of teaching clinics). It is the only time in my life that playing has been anything close to as fun as writing music or reading about theory. I wish I had done it far sooner.