TLDR: They'd get caught.
Imagine if you were a lousy skimmer and you maybe clone like 10 cards a day on one ATM before your shit gets found and you've to go elsewhere.
Now imagine if you were to cashout that shit in the vicinity of said banks: BUSTED!
Same with other stuff: Most people get caught by suspicious patterns: If you get seen daily cashing out on an ATM or purchase a shitload of stuff people will get sussy...
That's why those skimming are just at the beginning of the pipeline: They work with cloners and those with mules or others that transfer the funds...
So OFC that would raise eyebrows...