Exclusives and local multiplayer. Although, Microsoft seems to be porting exclusives to PC now. So, the only real exclusives you'd be missing out on are PS5 and Nintendo exclusives. I usually just watch Let's Plays of PS4/5 exclusives, but if you really want to have the game I suppose you could buy a console for it.
For me, exclusives aren't enough of an incentive to warrant getting a console. Might be for others, though.
Now, local multiplayer is a pretty big incentive if you're like me. You want to be able to get the gang together and play. Nintendo is best for that. Unbeatable party games. As for online multiplayer, PC is unparalleled (of course, besides the occasional hacker).
So for me it just boils down to if you want to be able to have a console party or not.