$1 cost seems like a big underestimate of the cost to me. Aside from the discomfort being able to see people's lips is useful in a loud environment.

I think nasal sprays are a more cost-effective solution.

FWIW I can't recall ever having gotten sick after going to a conference. I might get sick less than average though. I agree that you should definitely wear a mask if you have >50% odds of getting sick without one.

Thanks for sharing. The estimated benefits seem plausible for the average attendee to me. On the one hand, I suspect most people are at significantly lower risk of significant illness transmission than you believe yourself to be. On the other hand, the value of eliminating one week of an average EAG participant's work-preclusive illness is probably more than $1000. (A conservative estimate of that value would consider the total cost of employing the individual, not just their direct salary -- and that is often at least 2x the employee's salary.) Although the median infection will cause less than a week's incapacitation, productivity-reducing symptoms can last for a while even if the risk of long COVID is estimated as low. You could also count added value from reducing the risk of getting other people sick, not just the reduction in risk to the mask-wearer.

As Larks mentioned, there are some meaningful non-economic costs to consider. There's always the option of selective usage (e.g., yes during a presentation at which you aren't speaking, no during a 1:1) to mitigate some of the non-economic costs. You may have accounted for at least some degree of non-usage when you specified that mask usage "reduces my chances of getting sick even by 50%," though. Your analysis might be more robust at a ~30% reduction to accommodate more periods of non-use. 

I suspect the harder questions on a cost-benefit assessment would be between various flavors of "sometimes mask" rather than just no mask or all mask. It would also involve considering alternative mitigation measures such as testing. It sounds like you're more susceptible than most and have a favorable cost/benefit profile; people who have new onset coughing or sneezing are likely to have one as well. 

Intuitively, it's all been very clear (to me, at least!) - but thanks for spending time on making those calculations. An extra argument to convince sceptics is always useful.