You aren’t releasing music at the moment, but your quote above - that’s exactly why I finish tracks - just to prove to myself, that I can do this. I realized a good while back nobody - not even close friends and family - gives a shit about my music but me. Just seeing an idea through into a finalized form is quite an exercise in patience, determination, and perseverance. It has taught me a lot about myself.
Even if someone is the “I just like to jam” type, it’s worth it to at least make a small EP, just to see how it goes. No rule that someone has to make another one, ever. I recommend it. Now, I keep going just to have a personal musical diary of different periods in my life. Release publicly, or not, but a musical timeline of 20+ years will exist and makes for very interesting listening, even if by myself in my studio, on headphones.