I know I do to see what other images I might like but was just wondering how common that is. Do you look at other photographer's profiles to what they "have to offer?"

From a customer's point of view the only time I did this was with illustrations when I need multiple illustration in the same artistic style for the same project.
For photos I do not really see the point, at least for myself.
I think customers do it from time to time. I can even tell when a lot of images from the same topic are being sold at the same time/to the same location. But this only happened with some topics that I am heavily focusing on in my port. If you have a lot of photos from, for example, a certain location and a customer wants to write an article about it, then it doesn't seem too far fetched to assume that he or she might browse your port for more if he found one photo he/she likes through the search.
But I don't think a pohoto editor who is searching for a single photo of, for example, a smoking elderly woman, finds one and then randomly browses a contributor's port when he is not looking for any more images of that topic.

Yes, like other people said - if I need something in a series/different poses/etc.