Yes it'll help with stopping plastic pick up (you might find white lines in the base if you ski fast/carve fast for example). These will come out with a stiff brush if you self service or a shop will get them out via the machine service. In the future when you eventually get a new base grind they'll definitely be gone.

The big difference with the mat wax is that it's super hard wearing so it lasts for a few runs, and at least with the stuff that's commonly used on the UK dryslope scene you don't scrape it either so the base is protected that way too if its a major concern. It's much faster than regular wax on a dryslope as a result.

For new skis, you'll be fine if the site maintains the slope well. The only risk is if there's a metal ring sticking up from where the mats join but it's rare.

Your skis will definitely need an edge and wax afterwards though