@Areski I understand that (I've used both freestyle and dance skates). But, since I've used both kinds of skates I can tell you that you can still do deep edges, extension, gaining speed, etc. on both.
The only real difference is that dance skates/blades are that dance blades make turns and spins easier and that the back is lower so that you can point your toes better. Dance blades have a shorter tail end so that you or your partner don't step on it during the nice, tight footwork you're doing and no bottom toepick. So I forgive the difference in toe point - some of those freestyle skates are impossible to point your toes in. But it's no excuse for having no edges, not gaining speed well, having no/poor extension, toe-pushing, and scratchiness in their skating. Admittedly, having no bottom toepick is an advantage in no scratchiness, but if you have good skating skills you'll be putting your weight on the middle/back of your blade while skating, preventing scratchiness even if you have that extra toepick.