From an article about it:

Now, it should be stressed that this is a build of The Witcher 4 specifically designed to show off Unreal Engine's features. Yes, it's running on a standard PS5, but it's not necessarily indicative of the finished product.

So that's like saying "under laboratory conditions it has been demonstrated to work".

If you know what to look for you can notice it (mainly light bouncing of objects and tainting shadows with the color of those objects, such as the shadow above the green canvas here), but the difference to the non-RT version when one doesn't know what to look for is minimal and IMHO not enough to justifying upgrading one's hardware, especially considering that so much of the rest (the water in the streams, the snow in the mountains, the shape of the mountains themselves, the mud splash when a guy is thrown into the mud, the folliage of the plants and so on) has those visual shortcuts I mentioned.

Yeah, sure, it's nice than shadows next to strongly lit colored surfaces get tinted with the color of that surface, but is that by itself worth it upgrading one's hardware?!

When most games with RT in them deliver that performance on one generation old hardware and all environments, then you will have proven the point that for most gamers it has no significant negative impact on performance.

If you think that video is representative of the release game's actual performance and fidelity, I have several bridges to sell you.