I don't think option trading not on full, liquid exchange can work well.
Selling options is shorting volatility (a bet that implied vol will be higher than realized vol), which needs to be hedged. On exchanges, hedging automatically provides collateral, ie. sold atm call option for 1 btc is perfectly hedged by a ~0.5btc long, so even at impractical 100% collateral, you only need 0.5 btc more. The total is always 1btc.
On a purely options exchange with 100% collateral, you need 1 btc + enough collateral to go long 0.5 btc on another exchange, and in the worst case, enough to go long 1 btc. That's two times more expensive and requires additional hassle.
You do not necessarily need to hedge your exposure to volatility when selling an option. This is only true for entities that trade options professionally to make money off of the changes in pricing of options. There are plenty of "non professional" reasons to trade options (for example to speculate, or to generate additional income).
In order for an options exchange to work properly, it will need to have some kind of central clearing house that guarantees each trade, and the clearing house will need to demand that the other side of the trade put up sufficient collateral (bitcoin/fiat to cover a short position being exercised).