Personally, I find blitz is less about pure tactics, and more about making and enforcing a plan, and then the tactics stem from that. A lot of new blitz players will get into the middlegame and not really know what they should be looking for, especially when there simply aren't any tactics in the position, and that's where having an opening you know the rough middlegame plans for comes in handy.

For me, as black I play the Pirc or the Czech Benoni. Generally, I know that I'm going to be pushing on the kingside once I've closed the position, so I go into it having a clear plan and largely sticking to it. If I blitz those moves out, then suddenly I have more time when I get to the critical position.

I'd compare it to a set play in a sport (e.g. rugby, or American football). The attackers have rehearsed a move to break open the defense and gain an advantage (opening/middlegame strategy), but also need the ability to improvise when they spot a defensive error (tactics), which they can then convert into a score (endgame)

Hopefully that makes sense -- feel free to ask if I've been unclear.