Beer afficionados and similar seem to adhere to some method of pouring beer. The reasons stated feel unscientific, and I'm wondering if there's any truth to it?
What I'm talking about is the method explained e g here: https://www.beeradvocate.com/beer/101/pour/
Steps to a Perfect Pint
Use a clean glass. A dirty glass, containing oils, dirt or residuals from a previous beer, may inhibit head creation and flavours.
Hold your glass at a 45° angle. Pour the beer, targeting the middle of the slope of the glass. Don't be afraid to pour hard or add some air between the bottle and glass.
At the half-way point bring the glass at a 90° angle and continue to pour in the middle of the glass. This will induce the perfect foam head. And remember, having a head on a beer is a good thing. It releases the beer's aromatics [...]
Another common explanation is that a foam head actually works as a "lid" and thus keeps the beer carbonated bettter.
Is there any truth to either of these?