When you work for free it's not just you who suffers. You undermine all your colleagues by comparison. You contribute to the exclusion of people from other backgrounds (older people, parents, people who can't afford reliable connections at home) who might not be able to make themselves available the way you do.

If you have meaningful ownership (not just a handful of probably-worthless stock options) then by all means work as much as you like. But if you're an employee then it's not as simple as just being your choice, you're forcing your colleagues into a race to the bottom. There's a good reason we have laws about e.g. unpaid overtime.