On the other hand, if I wrote a whole essay detailing the evidence I have for my claim, it would still be open to all kinds of objections, which in fact might well be valid [...] Therefore, I will let these assertions hinge purely on my own credibility.

If I follow, I don't think this is justifiable. It seems that you're saying that you don't want to talk about your arguments in detail because they might end up partially failing, or because you don't think your audience would be able to fairly evaluate them. Even if either or both of these issues are present, the presence of the actual argument still offers a better chance of understanding being imparted than its absence.

I'm willing to accept expert credibility as a proxy for a strong argument when time is limited, but not as a substitute for that argument. Furthermore, I think it's reasonable to assign reduced credibility to an expert that is not willing to provide their argument when asked!