I've played with pulling the fuse and I'll tell you my experiences. Yes, the ride height locks in place at any speed but you also lose the benefits of the adaptive variable suspension (AVS). As you may know, the AVS system is tied in with sensors to the brakes and steering that "prepare" for stops and manuevers (anti-dive and anti-roll). The shock damping seems to go into some mode other than "comfort" or "sport" that is underdamped and kinda bouncy. As for damage to your suspension... I can only think of ways it will damage indirectly. If locked in low mode, the suspension has very little up travel and little shock damping.. Take a look at the bumpstop and you'll see. This reduced uptravel can lead to broken lower A-arms. Just ask the Aussie's about their A-arm woes. Most any vehicle that is lowered should have uprated springs to reduce bottoming the suspension out. If not, hitting an offramp at 50mph and hitting a bump could be disasterous.
Furthermore, there is a bit of toe-out change when running in low mode. This could lead to increased tire wear and less stable handling. Of course, one could align it in low mode and fix that.
Just my thoughts. B)
Hoser, thanks for the info. I won't touch the fuse again.