If the bike doesn't NEED high octane fuel, absolutely. People used to run it solely to avoid ethanol, but that's history now, so IMHO you're wasting your money if the manufacturer says high octane isn't necessary.
But, some bikes and some vehicles legitimately need it due to high compression engines, non-naturally aspirated engines, or aggressive timing curves. Can most modern vehicles use regular in lieu without suffering damage? Yeah, for the most part...but not always 100%. But in order to protect themselves those engines will severely retard timing to avoid detonation issues, and pulling timing pulls horsepower - quite often a LOT of horsepower. And when that happens, people often push on the go-pedal harder to make up for it, using more fuel - so there are times when the "savings" of using 87 vs the 91 the vehicle calls for ends up costing you more in decreased fuel economy.
I owned a 1997 Grand Prix GTP with the supercharged engine. Required minimum 91, and I tried 87 a few times and it turned into a complete turd in the horsepower department - as soon as the boost started to come in you could feel the computer pull timing and the HP would fall on it's face.
My current motorcycle has a performance and rideability tune that fixes some shortcomings in the stock tuning, and that tune requires premium now, unfortunately. But the cost per tank is literally a few dollars difference, so in the grand scheme of this hobby, it is what it is.
