I will debunk everything you said.
it's more open spaced maps maybe if you like your military shooter in 'open world' maps then your choices are pubg and arma.
-Yes, there is a lot more open space. But there is citys aswell.
if you like fast paced shooters in urban areas which are focussed on competitive and not 'public server games' then pubg is probably a bad choice.
-Here you are wrong, you can easly run around and find fights if you look for them, just get a car and drive towards highly habbited areas.
50 man in servers (pub games).
-This is wrong, there is 100 players on a server, not 50.
-There is a FPP mode aswell, so that was not a good reason.
looting and camping heavily favoured even though you are forced to move if you can predict the small circle and get some easy sniperspot you can just camp and win.
-If you loot and camp you will never learn how to aim plus that you will get rushed down, it is way better to not camp in PUBG if you are going for the win. Camping will most likely get you killed while moving around will make you unpredictable.
seems to end in people lying down in grass waiting for each other to move and then kill each other.
-You can easly spot people lying down in the grass so that's not a good tactic at all. If you only lay down and camp in the grass waiting for other people to peek you will lose in 95% of the time since there will be players that shoots at you while you are proned.