(I'm assuming we're talking about this as a hypothetical talking point!)
I don't think it would be beneficial particularly no because this place is developing its own sort of culture and way of working and Reddit is over there doing its thing.
If Reddit came and federated, I think most places would defederate from Reddit on principle at this point anyway, as they've clearly shown that they wouldn't be making that move out of an interest in the philosophy behind the 'fediverse' (we've got to think of a better name btw - Febb? Febby? Febbster? Feddy? Freddy?)
But assuming they were let in and were integrated, the increase in trolls, toxic comments, inane communities, would be too much for Febby to cope with and I'd end up leaving, probably asking with everyone else currently here. Reddit is there for people who want it, Febbster is here for people who want it and if people want both they know where to find both.