I agree. I greatly prefer to remain engaged in a task or activity even when it's forcing some inactivity. I'll absolutely reflect on it rather than get shunted off to some extraneous thing in the belief that I must be 'productive' by putting in some cycles on something else. I will pay a price if I fall for that simple mistake. I'm autistic and REALLY don't handle context switching gracefully.

It's tricky managing this, sometimes. If you're working with someone and their context and state is very different, it's easy for them to be blind to whatever my context is, and demand responsiveness when I'm 'tuning out' (staying engaged to what's in-process). My best social behavior there is to gently resist, and then if the heat's rising, comply with whatever I'm being derailed into with gentle inefficiency even if it makes me seem like a terrible dimwit.

In this way it helps establish that something's going on, that I am not in fact effortlessly able to be derailed this way and that. It's not people's responsibility to know my state (particularly if I'm not insisting they keep track of it), but it's my responsibility to be reasonably honest about where I'm at with it.

At that point, it's on the other person to observe :)