In BL1 particularly, and BL2 somewhat, it was always worthwhile to take a look int he weapons vendors to see if there was a better gun. BL1 had some probability of giving you a legendary in a vendor. BL2 also has that possibility, but in 7,000 hours of BL2 I have found 3 legendaries in vendors.
In BL3 I don’t even look. Drop rates for legendaries, as well as good greens and purples, are so high that going to a vendor just isn’t necessary or interesting. Except for selling stuff and buying ammo, so all I ever interact with is ammo vendors.
Anyone see anything good in a weapon vendor?