It makes a difference if a lot of aircraft bumrush the field in bad weather- especially for the last guy to land while he's watching his fuel state... For ATC there are half as many radar tags/callsigns and radio calls.
Pretty useful too 'stateside for domestic admin movements of large numbers of aircraft. A few years ago we flew flights of four (four is what I'll admit!) to hurrevac something like a hundred training command aircraft. That emptied out the flightline amazingly fast and having to file fewer flight plans was just the silver lining.
Tower controllers probably don't mind watching the free airshow either.
