My motivation for recommending that people update R, RStudio, and their packages at the start of every course I teach is ... I see so many time capsules! As in, systems that appear to be frozen circa 2016 or thereabouts.
So I wouldn't say that everything needs to be bleeding edge, but some reasonable definition of current.
Why?
First, we don't want to bump into bugs that have already been fixed. I also show and use features in packages/functions that have come about more recently.
Second, even when we run into trouble (which happens with new stuff!), discovering and fixing bugs in current packages seems like a very worthwhile activity. Much more so than figuring out how to get an old version of X to work smoothly with an old version of Y. I like to spend my troubleshooting time on things that are likely to benefit the most people, going forward in time.
Finally, I think there's also an element of "if it hurts, do it more often". This post describes this idea in the context of software development:
You will always eventually have a reason that you must update. So you can either do that very infrequently, suffer with old versions in the middle, and experience great pain at update. Or admit that maintaining your system is a normal ongoing activity, and do it more often.