I believe BT is the addon Bartender.
And the click commands, are having the macro click each the assorted buttons.
And then have relevant macros on each.

There aren't delays or anything, so that won't be an issue (no botting).
But like the popular DK Manifesto style, you are essentially spamming one key.
Which in turn mashes several macros.
Anything on cooldown cannot fire off, and fails if that is "randomly" mashed slightly ahead of the others.
Further with the Global Cooldown, anything that triggers the GCD prevents anything else on the GCD from firing.
But if you mash quickly, you will pretty consistently get an ability that can fire off, at least once every GCD.
It is a very decent approach.

If you use IS Boxer...
You could do all of this software side.
Take a look at the DK Manifesto, either version... it is a video by mosg2.