No, 8GB isn't really worth it on the Pi since the kinds of workloads that use a lot of RAM probably aren't going to be done on the Pi in the first place.
Same thing really for the 4GB if we're being honest, most of the people using a Pi 4 are using them as media centers/Emulation devices, which will barely use up 1GB let alone 4GB. I think Tom's Hardware did a test last year or so that showed to really hit the max on a 4GB Pi, you'd need to be running Chromium with like 60 tabs, plus a couple other applications that I don't recall (I think GIMP and LibreOffice were two of them), so realistically you'll never hit 8GB unless you're doing like...hardcore workstation stuff on it.