The NAS recommendation maybe not be needed now. But if you plan to do lots of shoots for a long time, it maybe something to consider. The reason why I think it is important is because you have your photos on a single drive. With a NAS with 4 HDD/for example, you can setup the NAS so there is always 1 drive that can fail, yet you would still have all your content. You can do multiple RAID format methods(depending on the NAS).
If your single drive fails, you could easily be looking at $800(for a 2TB) data recovery bill. Or worse, they maybe unrecoverable. So a NAS that maybe costly, does give you something. Unless you really don't have a lot of content, and you are a very religious person about backing up regularly.
This also gives you the option to separate the tasks you do to different computers. For example, running print emails, connecting devices, and more Word, or Excel related applications on the PC, and share the screen and components, while leaving your new Mac as the dedicated editing machine.
But if you are an occasional user and don't have so much data to deal with, and can't be bothered...that is easy to understand.....you should be perfectly fine with a single drive...... and backing up in automated regular intervals....Which might get you into a TimeMachine(another cost/complication :-/)