In the world where for every PhotoPea there’s a hundred other failed ideas that never materialised; to consider the idea of “just create your own product” being simpler than dealing with office politics sounds laughable either because you are not aware of how difficult the former proposition is to a regular engineer. If it comes so naturally to you, it still sounds immature to not realise how rare such an ability is.
They are talking about using PhotoPea as leverage to work at a FAANG. This doesn't apply, his project is already successful.
You seem to be basing that question on the assumption that both options offer the same pay (or at least that both off "enough" pay). Working on your own project is a tremendous risk; and for every success story like this, my assumption is that there's at least dozens who fail or don't even make enough to pay their bills.
Working on a successful independent software project is, for a lot of people, much more desirable than working at someone else's company; in much the same way owning a startup company would be. But the key there is "successful", which is certainly not guaranteed.
Photopea is one of my favourite tools on the web. Thank you for making such awesome software.
As for the comment about working at a FAANG I'm baffled. In what world would working at a FAANG, dealing with company politics, reporting to managers, having employment reviews, etc. be more desirable than the freedom and satisfaction of launching your own project and being able to very comfortably sustain yourself?