I don’t normally do it but we are supposed to in my outfit. That rule is so ridiculous, it’s outrageous. First of all it does not improve safety at all to have a FA in the cockpit. That’s why many outfits stopped it. I’m not going to explain how easy it is to crash the plane regardless how many people are in cockpit as my message will be deleted but yep, totally useless. On the contrary it’s creating a distraction to the remaining pilot who instead of flying the plane is most probably talking to the FA. We already had one case of altitude burst in my airline cause the captain was flirting with the cabin crew while the fo was in the toilet and read back the clearance of a company traffic with similar call sign.