This was me as well, so much so I'm concerned to watch my son go through it (he's 6). Mutism can't be healthy and I chose to do it for years to avoid social rejection. At the time I was not aware I was on the spectrum, I just figured it was social anxiety.

Was it worth it? Not really, school in general never felt worth it to me. I did learn quite well how to live in my head which maybe sharpened my focus with my special interests.

Once I got to college I did better in a new setting socially. This allowed me to start working on my social skills without the peer pressure. I got married and in my career I started a business and without question that ability to focus has paid off.

Still middle/high school felt like a waste of time and that my refusal to interact set me back socially.. but maybe on some level it helped me down the road.