"Emulate - Match of surpass by imitation "
Imitation is a pefect way of exploring your own voice by trying to recreate the sounds of others - nothing wrong with that for practicing, but every singer should have their own voice and develop it
Bert's tone was improved (hardened) when he used the smile - that's why he used it
If you have a better way of producing and expanding your tone, of course you should use that, but if not, there is nothing wrong or "untraditional" about what Bert did - many singers have similar 'tricks' to produce sounds they find difficult
Ideally, you do the work internally, muscle control, or narrowing the sound - that was the aim of Ewan's voice and relaxation exercises
One 'external' invaluable trick for a singer is to drop your shoulders to lessen tension -
Tension is one of the greatest problems for all singers - it causes a lack of pitch control and shortage of breath
If it starts with a nervously clenched fist it ivevitably spreads uoo the arms and into the shoulders

You are making far too much an issue of this Dick - it's a technique and has nothing to do with singing style or interpretation - another tool in the vocal tool-box
Jim