While searching for references on a certain class of problems I came across a well-written master's dissertation. It did not contain much in terms of new results, but it did a good job of explaining what happens in the important papers in the field (or so I believe). This was helpful - my interest in that class of problems is that it's adjecent to the problem I'm writting about, so it's important for me for context and historical reasons, but it's not a subject I want to research in much depth; having read the dissertation and a introductions to some of the relevant papers, I feel I know as much as I need to know. I should also mention that some of the relevant papers are in French, so I was very grateful that someone explained in English what their gist is. I also feel that what I read in the published papers is enough to reasonably write all that I need to write in the introduction, but having looked through the dissertaition certainly helped me orient myself.
Now, my dillema is: Should I cite the dissertation? It is not generally seen as a requirement to cite expository materials on a subject, so I don't think I have to. But I also feel that it would perhaps be nice to cite it: it acknowledges that I benefited from reading it, and it helps potential readers who might become interested in the subject. If it was a published survey article, I would definitely cite it. On the other hand, this is a piece of writting that didn't go through the usual peer review process, and that was almost by definiton written by a rather inexperienced mathematician. I'm worried including the citation could annoy some readers, and possibly the dissertaion's authour.
What is the best course of action in a case like this?