Well dice can work but because this forum I think doesn't have a built in dice rolling system it can get a bit funky.
If dice are used the GM roles for all parties involved (typically) and brings down the hammer to smite those that aren't worthy! Sometimes you will know the dice roll, sometimes you won't, depends on the GM.
Some people are put off the idea of having to go to other sites and what not to RP. A lot of people just like narrative stuff as well I guess. I enjoy having an assured victory over someone or something and then the dice come into play and somehow we have to explain how a super hardcore badass with ridiculous weaponry is beaten by a skrub with a blunt knife...
I really don't mind having the Dice Gods involved. I think it adds that extra 'spice' to a game. But like you said to each their own, honestly I enjoy any style of RP. As long as you can have fun that's all that really matters.
I'm probably one of the only ones who GMed with dice rolls and most of the time when you're doing it for a 40k roleplay, you get fucked over really hard. I'm still experimenting with an alternative dice system and I think I got one that will work now, I just have to finish testing it. At this time though, it's highly unadvised to use RNJesus mechanics because most people here don't like being bent over every turn and then repeatedly fucked by the dice *looks at the Europan Conflicts*. I'll state it again, I offered to remove dice and yall wanted to be dominated by it so it was your fault
PvP works when players are 'fighting each other'. But often it is 'I beat your character' 'Nah-ah' 'Yea I do' etc.