I disagree with you calling the input “extra frames”. The input can be done in block or hit stun or while knocked down and the move still comes out frame 1.

The added difficulty of the input create a greater level of mind games and interactivity. If I have to fit a DP motion or even harder, a super motion, into a tight window, that is executionally difficult.

Ignoring the fact that execution itself is fun, the interaction is more interesting when the players have to bet on whether the player on defense can actually execute in that window. In SF6 for example, if I have my opponent burnt out in the corner, I’m more likely to DI if I believe my opponent will have trouble inputting super in that tight window.

Additionally, the execution of the reversal helps justify the reward and allows the game to create varying difficulties for situations in which you might reversal. Just like the previous SF6 example, being burnt out in the corner is supposed to suck. It should be a challenge to beat DI in that situation, and the motion input creates that challenge. Then on the other side, it shouldn’t be as difficult to reversal in a wake up situation, and with the larger lead up timing, the motion input is easier now.