I see it more as existing holders making an unbreakable pledge to hold it for a certain amount of time. It breaks the prisoner's dilemma that most coins are held hostage by. That alone is enough to at least attract new investors.
How can making a coin "unsellable" attract investors ?
You mean knowing that everyone else is locked in as well makes it more attractive for me to be 'locked in' ?
Knowing that there are existing holders locked in makes it more attractive to
buy more as it means you're not going to get your investment dumped on your head the moment you do it.
Hedging can be done in several ways. The least intrusive way is to make it voluntary for the individual. If these hedges are publicly known then that boosts the stability of a coin. The liquid part of the coin can drop zero but the hedged part of the coin will retain it's value until it's free again.
This means that investors that have coin development as a priority over price increase can draw a line in the sand and show other investors how serious they are about it.
will the hedged coins be taken out from the market? that's how hedging works with BAY?