For multiplats yes, you will get the best performance there is currently on console. I considered getting one with my 4K TV and the X1X does have other perks such as game pass and BC.
HOWEVER I love me some JRPGs, Sony first party IPs, Nintendo IPs, etc. With that in mind, I have no reason to get an X1X personally as it does not have a large portion of the games I care about and it is not worth it to get one when my PS4 and base X1 plays the same games regardless. Seems like a waste of money.
For those who do not care about exclusives at all and only want 3rd party multiplats and nothing else, I would recommend the X1X. Literally anything else however and they should opt for PS4 or Switch instead.