I own a couple of LULAs for my ARs and an UPLULA for my pistols. I don't use stripper clips, so the regular LULA works great for loading and UNLOADING AR mags. The LULA also relieves all pressure on the feed lips, and I'd have to think that that'd extend the life of the feed lips.
I just ordered another UPLULA for my youngest son, who received a Kimber Pro Raptor II for Christmas.
I'd have to opine that anybody authoritatively asserting that they don't "need" any assistance in loading mags has never tried either of the referenced aids.