It's so good because a lot of people have been waiting for a viable alternative to Reddit for half a decade or longer. It's non-corporate internet, the way it should be.
It was like Mastadon and twitter, once they meseed up they got replaced, and alternative services become popular.
Unfortunately reddit was the de facto place to find information and ask questing and be sure to find an answer, now the communities are actually split in half.
I really hope Lemmy will get better over time, we could create briedges like matrix for some popular sub*s