I discovered the benefits of spikes in the same way Tom Thiel did, though likely even more exaggerated with my then Boston Acoustics A200 speakers. These were wide and tall floorstanders, but only 7" deep, with a simple plinth only 4" deep. The 3 drivers were widely-spaced vertically. So the woofer rocked the plinth substantially on the carpet, which levered the tweeter back and forth (relatively) substantially. When a friend suggested using aftermarket screw-in spikes, the entire soundstage (such that it was) snapped into focus as there was now zero rocking and the drivers sonically 'aligned.'
Despite my subsequent CS2.3 and 2.4 having a far deeper base, I still notice the benefits of their included spikes -- on carpet over slab. I had the 2.4 outriggers, but sold them as their primary purpose seemed to stabilize the speaker from being knocked over by large pets or small kids. Moving the existing 2.4 spikes a few inches outboard in each direction had no audible sonic advantage, only less-visible low-lying arms to trip over.