You know, that's completely unimportant. The important parts are that 1) Starship stage is under pressure when landing and 2) pressurization makes a thin-walled metal cylinder much stronger resisting buckling. Details of how Starship works and how pressurization is historically used to increase strength are just to support these two points. But if you already have these two points, you should admit that the argument "Starship can't land on legs because there's too big of a risk of buckling" has some counterarguments. And the overall decision isn't as clear as we'd like to have it.
Actually, it is very important. Autogenous pressurization has a much higher risk of pressurization loss than a system which uses inert gases, due to the potential for the ullage gases to mix with the liquid fuel and condense.
This is relevant when designing the landing system.
