Dtilt out of shield is more useful than shield grabbing. If they are in the mid-percentages, then you may be able to lock them to kill percentages or just kill them when they pop up. I use this move a lot, and it is always decayed which seems to keep players tripping more.
If you see someone is about to escape the trip trap, then fmash or ftilt. This move also works great against metaknight. It takes the dash approach out of the game, and metaknight has problems DI'ing out of it. Meta's like to upB out of locks or combos like this, and it won't work in this case. I scored a big kill in a crew battle against Forte's metaknight because he kept tried to upB out. Most of them will think of this before DI'ing.
I know for sure that it clashes with kirby's fmash (been said it clashes with a lot), but it is one of his best kill moves so keep that in mind. Also, dtilt is faster so if he throws anymore out after the first, you will have to delay the dtilt a bit to continue to clash. I tested this in a friendly with a kid. We moved across the stage, but with each clash, he moved backward a little bit. He eventually was out of range and I let him whiff on a fsmash and punished with an Utilt. I'm not saying your opponent will keep fmashing, but the tilt will push them back a bit so it will improve your spacing.
This move is 100% essential to Zelda's metagame.