There is a big difference between Dynamat and carpet....besides just the price. (A box of 20 carpet squares does cost $50). I suppose you could just glue on standard carpet, but it would take 3x as long, and the job would be messy.
But Dynamat only prevents panel vibrations due to it's weight, and provides some noise blockage. The carpet absorbs sounds, much like the acoustic foam used in recording studios. In the old days, they hung carpet on the walls for the effect. This carpet is thin enough to fit these various places, which of course is a concern.
When actually placing a piece of carpet in there, you have to leave clearance for the stock panel clips and screws. But the whole job just takes time.....I didn't have to cut or modify any of the stock pieces. I just hope all the carpet stays attached.....the adhesive seems strong enough if the carpet is laying flat, or applied at 90 degrees. It will only take gradual curves. In some areas I had to use a bunch of smaller pieces....to get them to hold.
In any case....no big deal if any come loose.
One other thing.....this particular carpet does not soak up water, since it is entirely made of recycled plastic. This is important for preventing rust should any of it get wet. Water flows right through it......the adhesive on the back is applied in stripes, so there's airflow, and it will dry out quickly.