I'm wondering if there are any statistics on how many users actually use features like time alert and self-exception. I think that users who can control themselves don't need such features. Addicted players, on the other hand, are likely to ignore such features and look for any workaround just to keep playing the slots some more.
If it's just a notification coming to you in the form of an on-screen message and pop-up, it can easily be closed and ignored. A more effective way of limiting your betting is if the limit actually prevents your from gambling. If you activate an 1-hour daily gaming limit and the time is up, the feature would prevent you from playing altogether. You would have to come back tomorrow to begin a new session.