From the tone of your post I'm thinking that you've made up your mind on this point, but there really is a lot of richness and extensibility in R which isn't available in Excel. For instance my blog is written in an R library called Blogdown, you can process 5 GB datasets on your laptop, send a reproducible analysis to a colleague, stuff like that.
I guess the thing I would ask you to consider when thinking about this stuff is the amount of time you've spent learning Excel. At the time I was learning R I probably had several thousand hours of focused Excel practice under my belt, and I could do a lot with the tool. So Excel was a way better tool for me than R because I was an Excel expert and an R novice. After now putting in about that same amount of time working with R I can say it's a much more powerful and extensible tool. But if you mostly work in areas where Excel...uh...excels, then there's no real reason to make the switch.