So you either don't work there as a parent or you become the caricature father from the 90s movies that misses all of his kids' games, fails to pick them up from school (although we solved this with Uber (TM)) etc.
At least they are being honest and upfront about it, IMO. Much better to do things this way than to do what some other companies do: promise 40-45 hour work weeks yet shame/withhold bonuses and raises to anybody not putting in over 50 hr/week.
Does Stripe compensate employees for working nights, weekends, and "paying attention" (really, being on call) off hours checking email? Or does it get rolled into the usual "salary"?
This paragraph is to me the number one indicator for a healthy and respectful company culture:
"We work hard to staff projects realistically. If overtime is needed we either compensate you by paying for additional hours or you can take the time off later."