Based on the Filmation cartoon, could someone please tell me about He-manís powers and need for a secret identity?

The way that Superman hides behind Clark Kent, when I watch the cartoon as a kid, I assumed He-man was the same way with his Prince Adam identityÖ I probably thought that way based on them having the exact same physique and look. Abiding by this scenario, I believed that raising the sword simply changed Adamís princely wardrobeÖ ummm, "disguise" into He-manís battle outfit.

But, now that I think of it, is supposed to be more like a ďShazamĒ situation, where Prince Adam is a mortal and only gets powerful upon saying a phrase and having the sword with him? I may be putting waaaay too much thought into this but if you were vulnerable as Prince Adam, wouldnít you just change into He-man one time and remain that way indefinitely?!Ö --maybe then only change clothes when needed.
Is there a reason he needs to conceal his identity from his parents and Teela, and a backstory why he only shared it with Orko and Man-at-Arms (like the introduction sequence describes)?

Thanks to everyone that clues me in and gives me their interpretation or referenced information, since I havenít seen all the episodes or read the books.