That depends on when you buy and how much you spend on it. There will always be a range of hardware for different budgets and the low end for the foreseeable future won't be really good for 4K gaming. But who knows what's to come in say 2 years time, by then Nvidia will most likely have another new generation of hardware.
I agree with you, if your hardware is capable of doing a task that you need then why not use it. I have several PCs for different things, I just built a brand new high end gaming rig for my Windows gaming, I moved my old PC over to be my new HTPC and my old HTPC got put out in the back room for now until I find a need for it. I even have an old ass laptop sitting beside me running Linux though I rarely actually use it for anything other than tinkering.
lol