I personally feel assigments should be given regardless. Practice makes perfect, the more you practise at getting solutions to math or problems in other subjects, the better you'd get at it.

The best students are known to have spent extra hours working on problems or just continous reading to assimilate. The memory is such that even after being taught, if we don't go back to read or practise what was learnt, we forget the details in hours.

So assignments should be encouraged but not in a way it becomes a burden.