So the Bayesian is reasoning based on what he doesn't know i.e. that the coin could land either side because his guess as to which side is heavier would be a 50

So the Bayesian is reasoning based on what he doesn't know i.e. that the coin could land either side because his guess as to which side is heavier would be a 50/50 guess - not the actual outcome. Frequentist bets on the outcome regardless of what he knows i.e. that the coin will be more likely to land on one side than the other and it doesn't matter which side that is. Isn't this just two different perspectives: Slicing vs Limits. Bayesian is concerned with outcome of a single trial; frequentist is concerned with the sum of all outcomes.