This is very important. The upscalers built-in to displays work very well for video, and might also be acceptable for text (of course, YMMV).
And if macOS recognizes the display as Retina (either automatically or via third-party software), you can use Apple’s scaling, which looks very good and shouldn’t affect system performance unless you’re running GPU-intensive software (and if you are, you can probably turn off scaling during your rendering sessions and turn it back on when the rendering is done).
And yes, I’ve posted several comments all about why 2x scaling is better than fractional scaling. 2x is better, but fractional still looks very good and won’t impact system performance if you’ve got lots of GPU cycles to spare.