VAR..dont roll your eyes!

OK just a question about this VAR after watching the world cup today.....France got a penalty but the game went on as the ref said no and about 15/20 secs later he stopped the game and went to consult the VAR tv and then gave the penalty the same just happened for Peru in the Denmark match with again the match continuing until the ref stopped play after being called to go check VAR...and again gave the penalty.....Now a couple of questions really...one is why was the game not stopped whilst VAR was being checked? because secondly what would of happened if whilst its being checked the other team had scored?..the Argentina game an appeal for a pen was not given by the ref(not talking about pen given and the one messi missed)as he reckoned the argie player had dived but tv replays showed it was a penalty but because the ball had gone out of play and then restarted with goal kick VAR cannot be used!! I also thought that VAR was to assist the officials and he can still stick with his original decision but apparently not....whilst I am still not sure it was a pen to France others did that is football but this VAR mmm not so sure right now.