one more segment ... you can also use SDC to generate that for free rather than buying it for $150.
+Ps can be valuable and you can check the +P clearance thread for that. Finding immediately confirmable options is very difficult (but not impossible) today.
The bigger benefit of Platinum may be the access to IN inventory. IN continues to be >> I on many routes. If you use your miles for UA Polaris awards, then Platinum can make a significant difference.