Photo above is Edith Traina at age 97. A youthful 97 for sure due to many years of fitness pursuits. I think those are 50 lb. plates so she is lifting 145 lbs. Not bad for 97.
You can join that organization AARP at age 50, so I guess that's "mature." Another measure of seriously "mature" is if you remember Jack LaLanne - the Godfather of American Fitness.
Should "mature" people (50-80+) do powerlifts? Of course, and should push the weight as possible. The Maggie's General Fitness protocol calls for heavy weights only twice weekly but that's partly because it's designed to fit in all of the other aspects of fitness.
However, a group of people, whether mature or youth, male, female or confused, care mostly about building or maintaining strength and physical sturdiness. Getting buff and sexy. Like people who only want to run, they are not after balanced fitness. To each his or her own although I will debate you on the value of the single road (and Mark Rippetoe and Glenn Reynolds might debate me back).
For mature adults who want to focus only on strength, 3 days/week of heavy weights is right with the emphasis on powerlifts. In fact, I can see some value in myself occasionally taking two months to do heavy weights 3/wk to see if I can get past my current plateau. Especially in winter when hiking on ice is not fun or even sensible. Hmmm. I have to mention, though, that I had a pal who climbed Mt. Washington in January. Kudos to him, for sure. Tough SOB, Vietnam vet. Once was enough for him to check that off his bucket list.
Powerlifting Workout for Old Guys