Is there a difference between creating a variable as a blackboard key selector and then setting the value for blackboard or just doing get blackboard and then setting the value?

[the_bat_2102]

Earlier I used to create a variable as a blackboard key selector and then set the value as whatever data type I want to.But I noticed a get blackboard method too.Is there any difference between the two,because if not then I can just use get blackboard instead of creating variables.