"Since I founded my startup ..." <-- the underlying comparison is between "working at a startup" (which is understood to be a non-founder status) and "working at a large firm".
As far as internships are concerned, internships at large companies are generally more flexible regarding roles. Some even involve rotations, where you get to see a little bit of everything.
You are right with that, and I do know what you mean. However my real point was that you can't really generalize things and make a checklist-based decision on those two, or in my case three (with founding) alternatives.
I personally think you should not make this decision on a too much numbers/status/fact basis, but on a very personal or you risk to regret it sooner or later.
As far as internships are concerned, internships at large companies are generally more flexible regarding roles. Some even involve rotations, where you get to see a little bit of everything.