I would still point out that hauling the entire 2.1 system around requires a fair bit of bother and cabling, which is fine if you’re okay with that, but the OP was pretty specific about getting the most out of the built-in speakers, and had little time for setup.

In that specific scenario, I’d still recommend a very inexpensive sub and one cable to it, and still rely on the built-ins for the top end. But buying the whole 2.1 Logitech system is still affordable, and it gives you the option of adding the satellites for higher volume/more time to set up gigs.