My opinion. Effortlessly implies that no effort is necessary to appear MC, it just comes naturally.
An example is they have no special ‘telephone’ voice. They always speak the same RP in any situation. Not worried about what they wear, how they appear, the scruffier the better sometimes, so it’s all effortless.
The rest of those to whom it doesn't come naturally make a big show of it, lots of expensive stuff, clothes, houses, cars, jewellery, stuff. !
I know my place. 