I mentioned it with Utena later half and Big O but it’s absurd when anime used digital openings or endings, but the main episode is still cel, that is a common practice I noticed with these late 90s and early 2000s anime
I forgot to mention it, but one that could have benefit was Kare Kano (His or Her Circumstances) as this anime feels very rough, as it was transfered from tape. (like how Carranger to Timeranger were done on D-2 Cassette tapes or the Laserdisc mess of Star Wars that was the offical GOUT)
Keep in mind, Japan tends to use 16mm or at least some cheap film.