The chains let the deck "float" over bumps and uneven terrain so you minimize scalping and, as said, it offers protection to the deck for damage sustained while hitting obstacles. If you look at the Raptor SD, the linkage drops actually allow for movement like chains would, but not as freely. Bear in mind the vast majority of homeowner yard tractor mowers have fixed deck drop...so in that sense it is not a real detriment provided your yard is essentially level. Of course, pro mowers want a chain hang as they don't want to scalp a paying customers yard. If you scalp your own, well...you can beat yourself up or let it go. But if you paid a guy, you'd expect not to see that.