The argument is that the player and team is punished because the player misses 10 minutes of the game and the team is down to 10 men
There is therefore no need for additional sanction
The idea hasn't worked because the punishment is quite severe. This makes it 'high tariff' for the referee. At grass roots, referees are therefore frequently ignoring dissent or wrongly classifying it as something else, most often Adopting an Aggressive Attitude. The rule is not applicable to Step 4 and above for good reason... it wouldn't work
The stupidest bit about it, is the prohibited use of a red card in certain scenarios
Sin Bin can be effective, but I'd assert that it's an 'advanced competency' to get the outcome the referee (and FA) wants. Enhanced Respect
The Stepped Approach can be tricky to judge. Use a Sin Bin too early and the referee loses respect, use it too late and respect has long since gone. The Goldilocks Zone is not easy to perfect and is often beyond the competency of those referees Sin Bins were dreamt up for