In practice, you don’t have to actually award the half-point for each dame for using the half-counting method. Instead, people can just count the unfilled dame and subtract it from (361 + komi) to get the total number of points shared between White and Black.
I’ve never heard this one before. I think that area scoring rules are actually much easier to understand than territory scoring rules. I think the only tricky part, for Chinese rules in particular, is being aware of which cyclical patterns can cause a “no result” vs which are forbidden by superko (other area scoring rules, like AGA, NZ, Tromp-Taylor simplify this to just always applying a superko rule and doing away with “no result” outcomes).
By the way, under the Japanese rules, players are technically supposed to fill in all dame (except those that must be left open to preserve sekis), since the definition of seki depends on which stones “possess dame”, which is a phrase that has some degree of ambiguity.