What is the difference between time-limited apps and time allowance apps?
Time limited apps is to allow kids to use some apps ONLY during specific time slots. For example, you want them to watch youtube or play some games only from 6pm to 8pm.
The daily allowance is the total amount of time that you want to allocate to some apps. For example, you want them to watch youtube or play some games for total 1 hour each day, and you don't really care when they use it.
By the way, you may also combine them to get exactly what you want.