It's really preference. Some people care that points be more equally valued per position. While others really just accept they're in a PPR format and draft/play accordingly.
PPR just adds another wrinkle in the fantasy game. If I'm trying to win a PPR league, I don't complain about an opponent's 8/33 game because I understand that's how our scoring settings work. I also understand that WRs and RBs that catch a lot of balls are more valuable than RBs who aren't known for catching. You'll only like PPR once you quit trying to make the RB and WR productions equal to your liking.
There are plenty of summaries written that give basic reasons why you MIGHT like PPR all over the internet. This one is from 2014, but pretty much gives you every reason that MIGHT convince you.
http://www.rotoworld.com/articles/nfl/47757/71/to-ppr-or-not-to-ppr 1. To increase the number of fantasy-relevant players. Examples:
"To make more players fantasy relevant which also creates deeper leagues."
"I think it helps make more players viable starting options, especially in larger leagues."
2. To shift fantasy value from RB to WR and TE. "I would say to level playing field of RBs a bit, also devalues QBs as result."
"Rewards players. RBs that can catch the ball > RBs that can't catch."
"I think the original reason was to increase the value of WR (and TE a little) in relation to RB."
"The NFL is a passing league and standard scoring weighs RB value too highly."
"Originally, it was to balance RB/WR values. Not sure it achieves that anymore, tho. Hence the proliferation of PP1D." (PP1D = Point Per First Down; we'll cover that later.)
3. To reduce the impact of touchdowns, which are less predictable than yardage and receptions. "Take luck out of the game a bit. Scoring often times luck vs number of receptions."
"To mitigate TD's. The standard system is too TD-centric."
"Puts less emphasis on TDs and more emphasis on categories that carry less variance, thus more predictable and more game of skill."
4. To reward real-world value. "To give value to WRs that consistently move the chains. In real football 5 receptions for 50 yds is good, but not in standard FF."
"Isolates and rewards the singular essential purpose-fulfilling act of being a receiver of the passed ball: the reception."
"To both further reward volume-heavy WRs and 3-down RBs, and increase the total number of usable players in deeper leagues."
"Increases quality of players. Guys like Sproles/Welker become top 24 while the
Mike Wallace's drop in value."
"Give points to those who had an impact on the game, example: catches a few yard catch but it gets a first down."
5. To make things more fun and exciting. "Simple: it makes it fun. I played in both last year and it's simply just more fun."
"I think it's just an added scoring method to make it more exciting."