You are right, I was mistaking planar reflections with cubemaps.
Still, there are ways to optimize planar reflections. Some are similar to what is done in RT, such as using lower LODs, for the proxy world. Culling of hidden surfaces and things out of the FoV. Etc.
On the other hand, it would not have the same issues with noise and render lag that RT has.
aside from reflections, i am honestly not seeing a big issue with rt noise. DLSS cleans them up rather well and all the examples he gives are hard to notice. You HAVE to be looking for them. especially the indy and alan wake 2 examples he gave.
honestly, aside from reflections on moving bodies of water, i hardly ever notice these things. Path tracing with ray reconstruction in the beta phase had the noise and ghosting that was actually immediately noticeable but they fixed that by launch. The rest? meh. I never noticed any issues with star wars outlaws reflections, cyberpunk reflections or even with ratchet that hes pointing out here. Why would i ever look at reflections on the ground anyway.
the water shit does need to be fixed and is definitely annoying, but the ssr artifacts in dragon age broke me. I hated how they just added a giant fucking halo around my character. its way more immersion breaking than any annoying rt noise. again, its mostly limited to moving bodies of water like streams. i didnt see these rt noise issues in dragon age's ocean or window reflections in spiderman 2.
this is a good video, and im glad he made it, but it's not as bad as he's making it out to be. Rt effects in outlaws, avatar, dragons dogma 2, are exactly what separate them from last gen games.