Even the controlled test with only dragon kick - twin snakes - snap punch you see a rather quick decline in overall damage done. At 20 seconds of the parser timer (the moment you hit GL3) your macro right side is behind 1200 total damage done approximately. At 1:44 parser time your macro right side is behind 1900-2000 approximately while GL3 was maintained.

Your own example shows a rather quick degradation of damage. In a longer fight (you end your example at 1:47 parser time), this gap will continue to widen due to the delay.

To be honest with you, your macro would benefit the casual / midcore group because majority of them can't even be troubled to push 4 buttons so this is right down their ally. But sadly this is something that couldn't be used competitively in endgame content.