If you do not have a 4k Display to watch the 4k content, there's not going to be a whole lot to be gained from the 4k Cameras for your current computer setup, however...
Even if you don't have a 4k Display:
1) your computer will still most likely play the 4k content, it'll just be downsized in resolution to match your display. If your computer is ancient, it may not be able to decode the 4k content quickly enough to be playable, though. If you're on windows, you could type in the search/run box "dxdiag" and tell us the CPU from the first tab ("System" tab) that opens, and the graphics/GPU device from the "Display" tab. The community will be able to provide further guidance from there.
2) you will still be able to upload to YouTube or other Streaming platforms the 4k content. Even if your computer can't display it in all its glory, others can still enjoy the 4k content.
3) you'll still be able to use video editing software to edit or splice together 4k content, for later, to be uploaded, or just to archive.