"Strictly speaking, your statement is true, there are many other things you can do, all of which will bring you experiences. However, startup experiences are unique and not easily fungible for other experiences. The question then, simply, is whether you want startup experiences. If not, then you probably should not be working at startups at all, even if the pay was great. But if yes, then I think you'll walk away with experiences that will seem very valuable to you, and worth the opportunity cost."
The other way to get startup experience is to start one yourself. You get the experience running a startup and the risk/reward ratio is much better.
Assuming you have the money to do it, then sure, but you are risking your own money. We all start out making mistakes, and if you can learn important things while someone else pays all the bills, then you are better off in the end.
The other way to get startup experience is to start one yourself. You get the experience running a startup and the risk/reward ratio is much better.