I think so, at least in environments where OOP is the base metaphor, like Ruby or Python. I can't think of any major impedance to creating meaningful class diagrams for, for instance, a system of ActiveRecord relationships. RubyMine (last time I used it) actually will generate a nice class diagram for you based on the given ActiveRecord/schema definitions.
For me these days, since not many coders use it, I find UML mostly helpful as a personal tool I use to understand a new codebase or a complicated design/data modeling problem.
I also find sequence diagrams really helpful, particularly in complex async, service-oriented environments where many times there's just too much state to track and too many moving pieces to really see the essence of the problem.
UML is not everybody's cup of tea, but I continue to find it a valuable way to visualize complex code relationships, often times surfacing problems/solutions that would not have been as transparent just from reading the code.