Will reducing mysql permissions hinder WP function? [duplicate]

WordPress absolutely does need “DELETE“, otherwise it has no way to delete posts or tags or options rows or anything else.

The “DROP” command is sometimes used during upgrades, although it’s been a long time. The last time I think it was used was during the WordPress 2.3 update, which removed the assorted categories tables in favor of the new taxonomy tables. I would not say it is safe to remove it, but I doubt it would cause you any real problems for now. A solid backup plan in place is a better idea than removing it. Frankly, if something gets to the point where they can run raw SQL commands on your system, you’re already in trouble, denying DROP won’t help much.

Plugins will occasionally create their own tables and do things like this. DROP is pretty rare though, except during a plugin uninstall process.