That's the difference between limit and no-limit. Everywhere I have played limit the whole buy in comes in one denomination. In 2/4, 3/6, and 4/8 it's typically singles.
(In my other posts in this thread, 8/16 is played with 2s and 10/20 with 5s.)
The advantage is there is not need to make change with bets, and all actions are clear.
The volume of chips does not negatively impact a limit game because there is never a need to count a stack unless a player's stack is short of a full bet.
Obviously in no limit, you have to count stacks rather frequently, so you would rather that be fewer than 100ish chips. So you tend to get higher denom chips and just a few for use in blinds.