Pros
A seed-stage startup is the wild, wild West of business life. There's little infrastructure to support you because you're building it. Your work has a hundred times the impact it might have at even a Series B startup. You're paving the way for future employees.
But in terms of day-to-day, the work here is almost always novel and reward creative thinking. You'll work hard but are incentivized to work smarter, not harder by the sheer amount of things to be done. Seeing ideas become reality over the course of days or weeks is quite rewarding.
Team is expanding rapidly but remains trustworthy, reliable and fun to work with. Workplace culture is something that comes with time, especially as the company develops and grows out of pandemic-era remote work policies. Joining anytime soon after this review is posted means you're going to get to play a role in that.
Cons
A cushy and catered job, this is not. The "wild wild West" analogy is a good one; there's little in the way of common creature comforts such as you'll see at even a Series A - yet. If you're aiming for that, you're likely applying at a better-known startup, anyway, and that's quite all right. But don't come here to be handheld.
Workplace culture and inner-company support is very much "under development" and probably a low priority for some time, as it should be.