We're about to drive down to Mexico
to (among other things) bring our full-size folding bikes back home. We never used them in Mexico, only in the US on the way down, because
1) Too hot to ride a bike
2) Too dangerous on the roads, both traffic and road surfaces
3) Wouldn't feel comfortable leaving them locked anywhere
4) Plenty of cheap
buses and taxis to get around
We're not generally big bike riders at home anyway, but we got good use out of them while cruising in the US, both for sightseeing and getting stuff. We just haven't found any use for them in Mexico, but YMMV as they say.