I think that in terms of friendly battles they become personalized, that is, we can choose the maximum level of the rare cards since with that also each person can see some statistics of high levels of their favorite cards (for example if we have in a legendary card at level 1 we could occupy it at level 4 as in the cup of chaos) or instead of putting the levels the same as in the chaos mode that are the levels that the cards are.
as friendly battles do not have rewards that would help to make strategy and also give people an idea which card is convenient to level up for their strategies that would be all and thanks in case you read it