What is the aorist subjunctive tense in layman's terms?
It is an action without history or continuation. A "pure form". A definite outcome that will happen as a result of another stated action.
However if the subjunctive mood is used in a purpose or result clause, then the action should not be thought of as a possible result, but should be viewed as a definite outcome that will happen as a result of another stated action.
Linguistically, it just means that the verb form is "unmarked" - sort of like the "infinitive" of any verb today.
It is primarily a concern of ancient Greek translations (although it is in other old languages too).
Sometimes we can get too "tricky" in writing. A large vocabulary and finesse with the grammar can be impressive and do add certain value for those who also understand those nuances.
But, for a great deal of writing, clarity may be preferred over minutiae.