The <wait.#> tells the game how many seconds it wait before doing the next action. FYI, the game will only honour up to 60 seconds of wait for a single wait command.
The macro system does not honour 0.# seconds, it will round the number to a whole second. Thus, 2.4 would be 2 seconds and 2.5 would 3 seconds.
All skills triggered and honouring GCD in the game take 2.x seconds of cool down. This is why macros are less optimal than actually pressing the buttons yourself.
If a macro command is triggered while the action is on cool down, the game will just say it cannot perform the action and move with the rest of the macro, "skipping" that step.