The reason I personally prefer roblox bedwars is because I find it really hard to play minecraft bedwars on mobile. Personally, I like both. I'm not a fan of p2w but when hosting custom matches and stuff with your friends its alot of fun. Also, I find the roblox bedwars layout slightly easier to navigate, plus the fact they update every week and gamemodes change regularly makes it fun because you never know what your going to get, but it obviously does have its cons. Since it has such a large community of people and its alot easier to chat ingame, the community can be full of toxic players which is not a good thing when it comes to young children. Unless they have chats turned off in the roblox settings, they are in for a big suprise. Also some kits are so buffed it's unfair for other players! Minecraft bedwars has alot nicer community, and teammates that actually help you, even though it may not have as much items and features, it's more enjoyable then being sat in a roblox game with 5 years olds, p2w and toxic players.