You should use the Japanese comma. Fullwidth punctuation should also be normalized to half-width (without inserting whitespace).
I also think we should standardize Japanese anisong credits without whitespaces, even for Bandai Namco Arts (aka Lantis) who is currently standardizing around extra whitespaces. However, a number of editors insist on inserting whitespace even when there is clearly none.
I wrote a pair of taggerscripts to encourage people to focus on standardizing their own files rather than wasting time editing things back and forth in the server:
It would be nice if people could spend time adding (new) useful data rather than engaging in a tug-of-war over formatting of old standardized data.