No prob at all to plug a still good-profiled tire with such an emergency kit.
As long the puncture is round and not oblong, it works pretty well.
This demage on the pic did NOT keep pressure over a two week period and had to be treated by a professional tireshop who put a mushroom from inside to cover the small rupture. Now alls fine.
There are for sure more suitable means of repair, as mushroom shaped plugs, plugs inserted by a kind of gun, etc. But this kind of repair mostly ask for removing the wheel, which is sometimes not possible and/or costly.
I did not have real success with liquids within tires, just messed the whole thing up.