It's the only way I've voted for years. It's so nice to get my ballot and be able to take the time over a cup of coffee at home to research every candidate and proposition so that I'm making an informed decision.
The alternative is to give the ability to kneecap populated blue districts so that lines are 6+ hours long, dissuading people in those blue areas from voting. A real democracy requires voting to be easy, quick, and free, without prejudice. Voting by mail is the simplest and best solution for most people.
I'm not sure I've ever been nosey enough to ask other people how they vote, so you might be very surprised by how many people you know are voting by mail. Unless you're in a state that makes it complicated for no reason, it just doesn't make sense to waste so much time and energy on driving somewhere and standing in line and then feeling rushed in the booth or else risk a mistake that invalidates your ballot. Here in Virginia, I think it was just a one time application to receive my ballots by mail and I didn't need to cite any reason to qualify for it. It's just an objectively better process. You should look into how to do it in your state and try it for yourself. And if it's not easily available, you should be asking yourself why anybody would want to make it harder to participate in their democratic process. Forcing it to be an in person only option restricts it to people with enough time and money to be able to get to their polling place and spend significant time on what for others is likely a work/school day. It's targeted voter suppression.