I don't think most groups are giving priority to DPS for all Sands, or anything, so much as it is that most groups are giving priority to upgrading weapons with Sands, before giving them to people to upgrade their armour - and since most groups are (wisely, I think) giving Unidentified Allagan Tomestone priority to DPS before tanks or healers, at this point they've probably almost all gone to DPS for most groups. Once you have the i110 weapons, though, there isn't really a pressing reason to do the DPS any more specific favours; they've got everything they need to be able to do their part in pushing progression, and Sands at that point are just going to be making lives easier, no matter who they go to.