Bad-mouthing and telling you it's unnecessary aren't the same thing. You can use it if you want but Bacter AE is simply unnecessary.
And just like being unnecessary in the food sense, it's also unnecessary to do anything special for biofilm to grow. It happens naturally. On every surface in your tank. You don't have to do anything for it to occur.
Shrimp eat what they like the most first. If there's something in the substrate they're eating? That means they prefer it over other things in the tank. If they're picking through moss, they prefer that.
The TL;DR: here is that you don't have to do anything. Just let your tank exist.
And just like being unnecessary in the food sense, it's also unnecessary to do anything special for biofilm to grow. It happens naturally. On every surface in your tank. You don't have to do anything for it to occur.
Shrimp eat what they like the most first. If there's something in the substrate they're eating? That means they prefer it over other things in the tank. If they're picking through moss, they prefer that.
The TL;DR: here is that you don't have to do anything. Just let your tank exist.