In dice game there is no other play with more skills than you to defeat you. All you have is a dice which you need to roll and if results come in favor of you then you win. Another reason is that dicegames are provably fair so there are very less chances of cheating.
I have no idea what you were trying to say here.
Because dice in my opinion is the easiest game to play. As well as this game has long played. Thus, gamblers are familiar with gambling types of dice.
That's it! Very simple rules, or basically lack of it. Online dice are just like slots only with much faster rolls and no need to watch the animation. The game basically plays itself.