Seem reasonable considering that spending multiple dust outputs with a self-custodial wallet is also expensive comparable to an Exchange's higher-than-usual network fee.
Good, you must had thought this through before asking here.

Also since you're talking about dust amounts here, having those kept on Exchange isn't much of an issue in case your account is suspended
due to one of "friend's" deposit. (since you don't know where it came from)

If the projected amount isn't that much, go for it.
Just don't forget to withdraw once it reach the minimum withdrawal amount that is good enough for self-custody.