Black Knight Irios
Explorer
Magic item dailies (MID) are about choices.
If I can use any number of MID a day I don't have to choose. Many of them are minor/free/immediate actions which you can add to your normal standard action attack to power it up. Your players will have more options in an encounter.
Your players will have less to think about which power to use because they can use just another MID later, so one tactical factor is gone/weakened.
Personally I'm sure that it is not hard to track how many MIDs you have used a day. But I think it is much harder to choose which MID to use if I have more MIDs/day before milestones. Therefore, you choice is meaningful.
If I can use any number of MID a day I don't have to choose. Many of them are minor/free/immediate actions which you can add to your normal standard action attack to power it up. Your players will have more options in an encounter.
Your players will have less to think about which power to use because they can use just another MID later, so one tactical factor is gone/weakened.
Personally I'm sure that it is not hard to track how many MIDs you have used a day. But I think it is much harder to choose which MID to use if I have more MIDs/day before milestones. Therefore, you choice is meaningful.