I also like having options, but sometimes it's good to take the choice away too. Before Legion, most pug raids where ML and with loot being reserved / ninja'd and it happened frequently. It wasn't simply "Don't like ML? Don't join", since most were ML and you didn't have much options, not to mention the groups that would change the looting method mid-run, more than once. Personally I had a much, much, much better experience with pugs in Legion thanks to this (and Discord..
).
Note that I don't personally agree with forced PL for non-pugs, but allowing a Master Looter in pugs was just silly imo. For an organized group of players it is obvious that having the ML option available makes sense due to allowing a single person to distribute loot among the raid however the guild sees fit. This allows for guilds to decide which part of their raid they should strengten first, be it gearing the healers because the raid is taking too much damage or the dps because of an enrage timer. It also allows for pieces of gear to be given to classes/specs that greatly benefit from it, so you would give gear with Crit to classes that greatly benefit from that stat, not just give it to someone because it's slightly higher iLvl.