We actually have terms for this.

"Efficacy" is how well something works under ideal conditions.

"Effectiveness" is how well something works in the real world.

So yes - "This is more effective because adherence is easier" is both true and intended.

Just so where clear, from a public health as opposed to basic science standpoint, that's a distinction without a difference.

people magically get more vigilant is as leakly as virus magically goes away on its own.

Yes, my phrasing was responding to the way the parent stated it as "90% more effective, and also it's easier to take". As you say: It's 90% more effective precisely because it's easier, not and also. Behavioral factors matter an enormous amount for the real world success of many types of drugs!