Musical death in VGC: Belly Drum and Perish Song analyses Part 1:

[evilsabre]

Personally i always see the most problematic part of belly drum is how telegraphed it can be in team preview. I mean if you see a slurpuff 99/100 times its going to be the belly drum set which and since belly drum normally needs redirection or fake out support to work it suffers heavily if you don't lead the duo. As a result i think belly drum reliant teams suffer heavily as unless you multiple strong leads to set up the belly drum you are pretty much forced to respect a counter lead your foe has to your preferred leads. Its the same reason i think trick room suffers a lot as the teams need pokemon that can function without that component of the team which makes building such teams very very tricky especially when you can only bring 4 pokemon with you.

Not to mention the simply existence of thunderous in the meta pretty much ruins the strategy becoming very strong as prankster taunt + a se attack on arguably the best belly drum user in the meta at the moment in azumarril as it can run a different set meaning predicting the belly drum can be a bit harder. The Kang + thunderous lead pretty much stops any chance of any belly drum lead you have working out meaning you have to leave you belly drum user on the bench or try to set it up after those threats have been dealt with which is significantly harder.

That said if you ever get the belly drum off safely you should have won the battle unless you misplay, so high risk high reward in the current meta with kang and thunderous being huge picks at the moment.