It doesn't intrinsically mean it's a great place to work.

The idea that Patrick works there and thinks it's a great place to work at is "lending Patrick's personal brand to stripe". If you have a lot of trust in his judgment (and thus his brand), you're more likely to think that "hey stripe is probably a great place to work" and then apply there, because if it Wasn't then why would he still be working there? Or why would he be endorsing it? It also puts his personal brand/reputation at risk; if Stripe Isn't a good place to work, that hurts his brand