Ohio's New Online Reservation System!

More and more states are doing that. In many the reservation fee is waived if you call in the day of the start of the stay (or if you call from the courtesy phone they may have at the park entrance, or something like that). It still stinks, in my opinion, even though I understand why they do it that way; it often makes it impossible to drive around a campground you've never been to and see what sites look nice to you and what ones would be annoying to camp in.

As to why they do it, things are much more straightforward for them if everyone is in the system with their sites. The rangers then can walk or drive around and readily compare the physically occupied sites to the ones that are known to be reserved and see if anyone is camping without paying, or in the wrong site, or whatever. It also should help avoid problems with more than one party claiming the same site, whether done accidentally or maliciously.

You have never been to an Ohio state park then. There are no courtesy phones when you come in. Rangers need to cover multiple parks so you might see one drive through the park on a weekend but they are not checking sites to see who paid and who didnt.