the way it should work imo is
you click execute you see the plans
you want the plans . fine click claim and get charged stamina
Or highlight the plans you want then click claim and get charged the appropriate amount of stamina.
This way you can use the feature only on the bosses you want. Because if all you need are relics, why would you want to execute the other 4-6 bosses?
you should have to at least click claim before it charges you stamina and awards the plans. Or at least warn you when you hover over the execute button pressing it charges you stamina.

The way it works now I believe is not the best, but I am betting it is this way because doing it other ways would lead to abuse of the feature.

I may use this feature as it is now a couple times when judgement hr bosses are released and in 2016 when sirius bosses are released, but I will stick with the old way most of the time.