I don't see any reason to limit myself to one or the other. As many others have observed, they offer different experiences as well as a few shared ones.
I will say up front that the notion that MMO's aren't social like TTRPG's is not my experience at all. I play MMO games with the same guys I play D&D with and we talk using Vent while doing so. Also there is a sense of camaraderie with us all being on the same team that I sometimes don't get at the gaming table where I'm frequently the GM.
My credentials as an RPG fan include having played for almost 30 years, written for Rolemaster and organizing a pretty darned successful local Game Day that has seen attendance by ENWorlder from all over the country. So in no way am I downing RPGs. But I think that there are things that MMO's offer that they do better than TTRPG's.
They handle combat mechanics extremely fast.
They let you try out lots of different character styles and builds in practice without taking up the gaming group's time.
They let you game when you want without relying upon the group as a whole.
They let you focus on playstyles that the group as a whole may not prefer by doing so on your own time. For example, if you really like PvP (which isn't supported in most TTRPG's that I've played) then you can go do so to your heart's content and still return on Saturday night to go explore dungeons with the rest of the group.
They let you explore something that you didn't have to create (again, as somebody who is frequently the GM, I like to get to play).
They let you fail. This one is actually one of the ones that interests me a lot. I like my RPGs to be challenging and I also tend to run games that can be very challenging (I earned my RBDM status). I hope that I have the challenge level dialed up to the point that the players think they are almost gonna die but then triumph. Sometimes a PC dies. Hopefully not too often because that kind of kills the fun for me if I have a constantly revolving cast of characters.
But with MMO games death is just going to happen to you once in a while. I like taking on a big challenge either solo or with my friends and getting my ass kicked once in a while. It tells me that I need to get more creative about my tactics or beware of something a particular bad guy is doing to kill my character. Some of my best moments in MMO gaming were losing a fight three times and managing to barely pull it out the fifth time. Course some of my worst times in MMO gaming were losing a fight six times and deciding that we just couldn't cut it. But that's the rub.
Anyway, I'm not suggesting that MMO's are for everybody. Clearly they just aren't some people's cup of tea. But I think it is silly to suggest that they offer no features that you can't achieve in a TTRPG. And, if you are fortunate in finding fun people to play with, it can be nearly as social an experience as sitting around the table. The drive is a lot shorter too.