Lots of game sales (or time played on a streaming service) means the development company stays in business and keeps the developer being able to make more games, so that's good :)
But personally as a game developer, I've never really cared about either metric. If someone has fun playing my game, that's all that matters, even if they only played for 3 hours, even if they played a friend's copy so didn't register a sale at all. I mean, it's how I view games *I* play. Sure, I played 540 hours of Animal Crossing. That doesn't mean I had more fun with that game than the 15 hours I got out of Just Shapes & Beats or the 10 hours from Cadence of Hyrule.
Most people I've worked with don't read reviews or watch sales charts or anything, they just move onto their next game. That's the most fun part of game development, starting a new game.
RE: 12 hours a day, maybe I've gotten lucky, but to me that seems like an overblown meme at this point. In my career, aside from a random 2 or 3 weeks of crunch towards the end of a project here and there, it's been pretty normal working hours. Only once was there a horrible endless crunch, which was indeed around 12 hours a day, 6 to 7 days a week, for 3 months, but that cost the company a lot of good employees, and they severed ties with the publisher that put them in that position.
