Once good technique is memorized by your vocal cords, then and only then, should a singer really “lose their technique” in a song. A good singer is one who has control of their voice.
A good singer knows their voice. They understand their chest, mix and head voice, and they know how to get through their entire range with ease and balance.
Test yourself….are you a good singer? Try a siren….start in your high voice and take it down to the lowest note you can sing while keeping the tone, the feeling and the vowel the same.