I wore one, and still do on occasion. If for no other reason than because it doesn't hurt. It "might" help, but it won't hurt. Plenty of people play the lottery because they "might" win. Others don't play because they know the odds are very low. It's okay by me either way. I'm not wasting my dollar on the lottery but I don't care if someone else does. Likewise, I'll wear a mask but don't care if someone else does.
I know they say masks are to protect others, and that cloth doesn't work very well because the weave is bigger than the virus. Even still, I wore it to protect me not everyone else. Even if it's only 1% effective at protecting me, that's a 1% better shot at avoiding infection than no mask at all. I came up with a "golf ball theory" in regards to how it may help (and I may be out in left field on this, but that's how I decided what was right for me with masks).
Say someone is going to hit a golf ball at you. You have a chain link fence that a golf ball can obviously fit through. You have the option to stand there unprotected and let the golf ball come at you, or you can stand behind the chain link fence. We know the ball can get through the fence, but there's a chance it might not. So why not stand behind it. Likewise, I know the virus can get through the weave of cloth, but maybe there's a chance it won't.
Obviously I'm not a doctor but there's no harm in trying to protect yourself. Since there was no negative side to wearing it, I'll take every miniscule advantage I can. Worst case, I wore a mask for no reason. No harm, no foul.
That easily passes the risk-reward test for me. Zero risk with any chance of a reward is worth taking a shot. That said, I can see where a low risk person won't bother wearing one. To relate back to the golf ball theory, some of us are standing closer to the golfer than others. If you're 300 yards away you probably don't care about the fence nearly as much as someone who's 10 feet away.
That said the government should not be mandating fences for everyone. You stand behind the fence if that's what is best for you.