no, absolutely not. IMO jab, U1, is only an optimal punish when you have no meter. I think you should never burn U1 unless you’re in the corner and you have an opportunity to get out by using it (and by extension putting them in the corner) or it will kill. st.lp, U1 is a 4f punish, but it’s too easy to miss. If you have no meter and you can get it consistently and it fulfills two of the reasons I listed above, by all means it is the optimal punish, but otherwise, it’s too much of a gamble and there are easier confirms.
Especially keeping in mind the situation it puts you in if you don’t kill the character, think of a Yun blowing a Genei Jin combo on an opponent with full health, right afterwards, he’s at his weakest because he has 0 meter (probably because he used Ultra and Super), and the opponent probably has full meter from eating the combo. You make yourself very vulnerable.
Edit: I can’t do it consistently, but if you want to practice it, you should practice it against blocking Balrog’s lk.smash, it’s -5 on block, but the st.lp punish is distance dependent.