Actually, the real reason I pre-study, is because I want to look up every Kanji in the dictionary, and and I can make a hyperlink in Anki.
For vocab, the reason is partly, I want to do EN->JP, and looking up words in the dictionary with a hyperlink. Another reason is core 10k breakdown.
I use reorder script to do Kanji first too, but I do all on the first day.
I might change my mind / strategy from level 46+ onwards, though.