For everyone who sees value in making the effort of going to vote and takes pride in always making that effort, like you and I do, there are a lot of others who are deterred by that effort and just don't bother -- and low voter turnout is terrible for democracy.
Which is why, as I said, I do not begrudge anybody the right to cast his or her ballot by whatever legally valid means he or she sees fit.
California (or at least Orange County, California; I'm not entirely sure if this is State-wide) has, over the past few years, evolved into a system in which everybody is sent an absentee ballot, but everybody retains complete freedom to either (1) mail it in, (2) hand-deliver it to the Registrar's Office or an official drop-box, (3) hand-deliver it to any polling station (not just the one designated for one's home precinct), (4) designate a courier to hand-deliver it, or (5) cast a ballot in any polling station. And that should most likely be the best solution for maximizing turnout: it accommodates those of us who see value in hauling oneself to a polling station (which I last did in this year's primary), without forcing anybody to do so.
Truth be told, for me, "mail-only" would likely be a deterrent: elections in the National Model Railroad Association are by mail (or more recently, online), and I've probably ignored more NMRA ballots than I've returned. Then again, I can't remember the last time the NMRA had more than one candidate for any office. It reminds me of a line in an episode of Mork and Mindy: on the planet Ork, it seems that elections amount to "Oh, you want to be in charge? Sure. Go for it."
BTW, I don't see as how Barr can come off saying there was no indication of any election fraud that could have affected the outcome. There bloody well WAS election fraud, at least in parts of California, and it was all over the news: the Republican Party was planting phony ballot boxes. There was one right in front of at least one Republican candidate's campaign headquarters. And they didn't even deny it; they brazened it out, claiming that they'd done nothing wrong! Sure enough, they predict fraud, and they fulfill their own predictions.
Kind of reminds me of all those claims that Obamacare would result in "death panels," arbitrarily denying life-saving treatment: sure enough, death panels DID show up. CORPORATE death panels, not GOVERNMENT death panels. Then again, some health insurance companies already had 'em.