Descriptive theory is a system of guidelines and properties common to music which already exists. Constructive theory is a similar system which aims to actually help create music. Thus while the former claims to be universal, the latter can be as personal and original as your actual creations, with any degree of overlap.
Whatever constitutes a particular theory, if it is not immediately relevant to some meaningful and immediate musical process for you, then yes, I can understand its irrelevance.
Perhaps improvisation, style doesn't matter, might be an excellent way for you to have some fun with both types of theory in a dynamic and pertinent fashion ?
I'm just trying to make helpful suggestions to keep your interest up; I know very little about common practice descriptive theory and my constructive theories are peculiar to me.