what is with the dreamcast dance pads?

[ΩOMEGAΩ]

So I just got 2 dreamcast dance pads, DDR 2nd Mix Dreamcast Edition, and a Nipponese Nightmare (MOD) so i can play it.

When I took out the dance pads, they were...odd...

There was the pads, and there was a plastic layer over it, and it does not stick well with the dance pad. Hell its screws you up even more.

so my question is this...

is there any reason why they made the dreamcast pads differn't?
why is there a extra plastic layer over the dance pads?

thanks.