The biggest advantage is that CRTs can have variable geometry pixels which match a lot of older resolutions and aspect ratios. While it's a lot easier to deal with non-square pixels on higher resolution displays (i.e. 1600x1200 can properly emulate a 1.2:1 rectangular pixel of a 320x200 display) CRTs still have effectively infinitely variable shaped pixels.
LCDs and their ineptitude with non native resolutions deeply annoys me. Sure, pixels in an LCD are fixed, but even resolutions that are multiples of 2 of their native resolution look like crap. 4K monitor? Surely it can handle 1080p, it's just dividing by 2; four physical pixels for one logical pixel, right? Nope! Looks like horseshit. Seemingly LCD monitors can't divide by 2. CRTs can handle any resolution within th…
Sharp-Bilinear[4] is also worth a mention, this is only available for some emulators, but allows integer-scaling-like quality without being restricted to exact multiple of the resolution.
[1] https://www.amd.com/en/support/kb/faq/dh3-034
[2] https://www.nvidia.com/content/Control-Panel-Help/vLatest/en...
[3] https://shmups.system11.org/viewtopic.php?f=6&t=67116
[4] https://github.com/rsn8887/Sharp-Bilinear-Shaders/blob/maste...