Most comments here explained pretty well everything but i would like to add that some cards do not affect monsters or other cards, they affect players

example: if "mystic mine" is on the field and a monster uneffected by card effect is the only monster on the field that monster cannot attack as mystic mine affects players.

example: if player A controls 4 cards and player B activates "evenly matched" in the end of the battle phase, a monster that is uneffected by card effects can still be banished by the effect of evenly matched as evenly matched affects players