Re: Control in the martial arts.
Understood - and I would pose the use question in a more granular fashion, really . . in terms of . .
Goals for training (generic):
Martial efficacy as determined by X criteria - MMA, grappling, fencing, felony street fights, etc.
Health and Wellness - How do I feel doing this training over time? This is more in terms of assuming you can conduct clinical self-assessments rather than thinking along the lines of "being in touch with your feelings".
Compatability with my life - i.e. a lot of purists expound on the notion that you give up whatever in order to train or be part of something. While I agree that nothing worthwhile usually comes without hard work and sacrifice I somewhat dispute the notion that you MUST give up everything to purloin knowledge at the feet of some master. This ain't feudal Asia and that mentality is far too easily abused by roleplayers and fakers.
That's before you ever get into the topic of Internal Strength . . the two schools of thought that I primarily see are . .
1) This is adhering to how "this stuff" is commonly understood across a spectrum of martial arts with the roots and source being found most "purely" in the sophisticated neijia forms practiced in China
2) This is how "this stuff" makes you more combatively effective through how I was taught and the innovations I made and transferred/trained into these outlets (DR, aikido, MMA, weapons, etc.)
I don't think 1 and 2 need to be mutually exclusive, however I don't think you can use 1 to justify 2 nor vice versa . . they are different things. If you're speaking towards internal power as trained along the lines of "six harmonies full banana neijia" . . then there's certain standards you're pursuing, defining or following. If it's a different martial art - then look to the source of the art (Cultural, primary exponents, parent arts, etc.) and their most common applications.
If you are training internal power as a skillset to apply across a spectrum of combative arts and have broken away from a "single-source" model, then while you are no longer bound to the "single-source" model as an art, you are more bound by the source of information (teacher, club, group, etc.).
Either way, I think a clinical discussion about some of the pros and cons of each can be fun - but ultimately doesn't change a whit how you actually practice it and apply it in your life/school/gym/etc.