Well if the choice is between per game stats and PER, I choose PER 10 times out of 10. PER is just the same thing as any boxscore stat, it just eliminates any guess work since it adjusts for pace and estimates the degree of positive and negative impacts of box score stats.
Hollinger has previously stated that PER is good at comparing offensive output, but does not account for defense. It also does not account for intangibles. I found an interesting rant on Wages of Wins site against PER and while I think that Win Share also has it's flaws, that the guy has a point. (ie. a good player, or marginally good player, on a bad team is more adversely affected by Win Share than a great player on a bad team, because superstars have greater effects on team wins. So while the superstars are accurately measured; imo, it's hard to account for players who not only are only slightly good, but would be great next to specific other players, but who are stuck on bad teams and thus never gets enough run with different systems to accurately predict how they would do)
Seriously, what happens between our players rookie and sophmore years and their aggresiveness on the offensive boards?? Completely unrelated to this post, but I remember Patterson was great at that too
The Rockets play at the fastest pace in the league, and Parsons plays nearly 38 minutes a game. He gets a lot more possessions than most SFs to accumulate those "per game" stats, and PER is rating player contribution on a per-possession basis.
Maybe the coaches want to tighten the transition defense? They've mentioned it being a problem. Under JVG the Rockets didn't go after offensive boards, he had them head back on D immediately. When Adelman came on board crashing the offensive boards was part of the game plan, but you can give up some cheap points from it.
PER does not favor low usage players. I like to look at PER/Usage. My rational is that guys with significantly higher ratios than most of the team may deserve a little more usage to raise the team PER average. Guys with significantly lower ratios may need a little less usage. Smith looks to need a few more touches while Delfino could dial it back. Parsons could use a few more touches, but he really isn't that far above the other starters.
Because PER is basically an offensive stat and his main strength is intangibles and defense. There is no stat that I know of that can accurately quantify these things.