They had an hourly limit that unless you were rare fishing (which is what the hourly limit is there to discourage) it wasn’t meant to effect you.
A daily limit of 120 was born from this 5/hour and that limit was unreachable by players in most cases. It also didn’t roll over to the next day. The 30/24hr limit is not a part of vanilla, goes against the vanilla design of letting player grind, and is far more restricting than the 5/hr daily limit ever was because it can be reached by doing 29 instances in a span of an evening and a morning, then You do the 30th and your locked out until the rolling resets of however many dungeons you did the day before and based on the time you did them.
The 30/24hr is badly designed, poorly implemented, and goes against the very design goals of vanilla.