MySQL has a lot of broken "features" that sadly some existing legacy code might be relying upon and there just isn't engineering capacity required to move to a saner DB, so they have to make do.

I had a legacy project on MySQL that turned out to only "work" because string lookups were case-insensitive in that particular version or our configuration. Moving to Postgres and its correct behavior suddenly exposed a lot of bugs we needed to fix before we could complete the migration.