Having worked at Lowe's, I'd venture that about 80% of the questions I got were variations of "Where is (foo)?" Usually they had a pretty good idea of what it was they were looking for, but not the exact name. They quite often knew they needed (for example) a joist hanger, but of the 14 different kinds we had they didn't know which one they needed. Thats 14 different kinds of *just* joist hangers. We had about 120 different kinds of nailer plates/menders/rafter trusses/ties/etc that are all used in wood frame construction and are sometimes called joist hangers. It can get a bit overwhelming for the customer that doesn't know *exactly* which one they need. In general, the only customers that knew *exactly* which one they needed were contractors and they had already bought them 20 times before.
It didn't bother me to help customers find items, but when the customer service manual says you should -walk with- the customer and help them (basically until they told you to go away) but the boss tells you you take too much time with the customer it gets frustrating. I completely understand why people get upset with the "It's on isle X" (and then employee walks away) type answer, but that's what some of the managers wanted us to do.
An item location service however it works would be good; but it would have to be fairly smart about helping the customer get the right name for what they're searching for to pare down which kind of joist hanger they needed, with pictures and a good list of synonyms for each product.