The iMac isn't even that great for aesthetics, at least if you VESA mount it and have a decent amount of external gear connected. I have the VESA-mount model of the 2017 27" iMac, and I end up having a bunch of cables hanging down that I wouldn't with regular displays. Additionally, I find it difficult to rotate the display into portrait mode because of all the cables attached, so I don't bother even though I'd occasionally like to.

If I had a separate monitor, I'd only have at most two or maybe even only one cable running to each display which would be easy to tuck away within the mounting arm. I'd be able to have most of my cables tucked away instead of the exposed mess of cables I have with the iMac.

To make things worse, they don't offer Target Display Mode like they did for a short while, so I can't use the iMac's 5K display with any other machines (e.g. work laptop when I work from home).

If I were buying today, I'd get a Mac Mini (and maybe an eGPU if I ended up unsatisfied with the built-in GPU), and just use my old 30" 2560x1600 monitor or get something like a huge 38" ultra-wide display (the 27" 5K is very nice, but HiDPI isn't a game-changer for me). In 2017, the 27" iMac appeared to be the best desktop Mac option (user-replaceable RAM up to 64GB was a huge factor), and I don't regret purchasing it, but the integrated display with no Target Display Mode is a massive disadvantage.