I had a genuine DashMat on my old Nissan 240SX. The only reason I had it was because the dashboards on those were horribly prone to cracking and cost a fortune to replace...everything in the junkyards was cracked to hell. They weren't uncommon for people to use to keep the sun off.
It's definitely worth it if you have car prone to dash cracks and you are willing to have a goofy piece of indoor/outdoor carpet on your dash. It saved me the $1000 of getting a new dash cap for my Nissan, so I thought it was a good thing. Eventually I forgot it was there. Just be sure you keep it clean.
On the Ranger, you've got a pretty good dash that doesn't look like it needs a lot of protection, but to each their own.