1) Having a Windows installed strongly guarantees that you are going to have a functional machine no matter what. Depending on your experience with Linux you might screw things up. If it happens you still have Windows as a back-up.
2) If your aim is to communicate research results, it is very likely that you are going to need to use Office at some point, to interact with your supervisor, colleagues, that don't care about OS and just run Windows (the majority of people). You can use Office within Linux but I find it much easier to use directly from Windows (reduces the pipework and focus on the science).
3) It maybe no longer holds, but a few years ago it was really frustrating to use and connect machines running Linux on a projector. For instance let's say you have to give a talk at a conference, you want to be 100% sure that it will work out of the box and that you don't have to fiddle around to show your slides. Windows does that really well (drivers are primarily developed for it I guess) and allows you to focus on the presentation only (stressful enough). I've witnessed numerous times good science being badly communicated because of this issue, where people try to tune the resolution for 10 minutes before starting and the slides end-up being half-cropped.
In summary, dual-boots guarantees compatibility with the outside world (science research perspective), and you can use your Linux the rest of the time :-)