The only time this combo is useful is when you want the damage and want to rezone your opponent, or if it finishes them off. Other than that it’s probably one of the dumbest combos to use since it puts so much space between gouken and the opponent, not to mention it doesn’t work on everyone and if you miss you will be max punished. Also even if you are able to land it, by the time you land and try to get at them, their stun counter has almost approached 0 b/c of long recovery and full screen distance between Gouken and the opponent.
Either use EX Palm > mp/hp palm or EX Palm > dash forward Cr. Roundhouse or some type of reset so you can keep the pressure on your opponent.
EX Palm > forward dash > tatsu looks very impressive but in the grand scheme of things it lets opponents off the hook b/c there aren’t any safe or good follow ups after you execute it.