A few months ago I did use this feature a lot. My linkages there haven't changed much, so I haven't made much use of it recently.
What I've found is that the weakness in the feature is me, or rather the limited degree to which I've gotten my personal library cataloged in LT at this point. Because I'm going around the house geographically, and my personal book collection is more or less organized geographically, this means that what's in my LT library listing isn't fully representative of my complete tastes and interests. I've entered a large number of religious books, children's works, and mystery novels, because those are the shelves I've gotten to so far, so the people who match me right now are those who have similar works entered. However, I have much more far-ranging interests, I just haven't gotten around to representing them within LT yet.
I did find a lot of people with similar tastes in mystery novels, but I don't feel a strong need to connect to those people. I identified a certain number of people with related religious collections, and was able to reach out to a few of them; but then I haven't gone to the trouble of hand entering a lot of the more obscure ones which would further identify our family within the greater religiously-read population. The one area where it really benefitted me is in fiber arts; I have entered most of my fiber arts publications, and I was very happy to be able to hook up with other people who have similar interests and tastes, based on the fact that they would bother to have shelves full of books related to sock knitting, knitted lace, and wool spinning!
All in all, I like the feature, but I don't find it changes much over time. Periodically I do take a quick look in case someone new has snuck in and gotten a lot entered that suggests I might like to make a new friend of them.