|leather is good:
-doesn't melt down like plastic when you slide on them
-better for perspiration
wrist guards or gloves (like other protections):
-help sliding on them, not burning your skin, avoid wood needles on wood ramps...
-should protect your wrist to break up to some limits
-some of them limit to much movments for hand plants
So the one you presented seems good, if you can remove one or 2 of the bars, you can still adjust their flexibility.