When it's available - absolutely. The point is to make the game look as good as it can go and also to immerse you (the player) into it as much as possible.
If you're playing a single-player game, it can make many scenes look much better and more realistic. With games that are doing the realism thing, it just makes it more realistic & immersive; especially games that give you lots of freedom. You can sit there and take in the sights - and when many games are going for realism, it makes sense. When you can soak in a scene in especially open-world games - it's much better, more realistic, and prettier to look at.
With something like Metro Exodus: Enhanced in particular (not the OG version) - b/c of the RT-Only in THAT version, it's one of the best looking games out there. It looks better than the old Metro Exodus version by a mile, IMHO - b/c they ditched the baked-lighting in the Enhanced version. And since it's built in such at atmospheric way in so many ways, RT only adds to it. Especially since it's trying to be very realistic in many ways (with atmosphere, realistic art design, etc), despite not doing so (i.e. MONSTERS!).
Given what we also know about Dying Light 2 - again, it's on some next-level stuff. And given the game's story, dialogue, and whatnot sounds like "meh" - yeah, it better do something else to keep me going & invested. RT features certainly will help - and since this is next-level type of RT usage, that makes it worth likely turning on.
There are games like say Watch Dogs: Legion, which isn't a great game by any means, IMHO - it's story & character stuff is very "meh"; and its missions are often repetitive (especially side stuff) - but, there's still something about cranking it up to 11 on the RTX 3070 and I can still can goof around the world and just roam, admiring how good it looks w/ RT On, especially at Night-time. Watch Dogs 1 and 2 are still the better game, TBH.
The other problem is - once you see it, hard to un-see it. I can point out shadows not looking right, light not bouncing right, and other stuff in older titles...b/c I've seen what RT does, especially from Metro Exodus Enhanced.