As a point of detail: Wingly / Skyuber don't "Pocket the money on unused gifts": they never see that money. Also: are you suggesting that people not cashing in their experience flight vouchers is really good for GA?
.... from their site....
You will receive the gift card immediately after checkout via mail and via Wingly notifications.
The card is valid for one (1) year, and can be used by any Wingly user until its credit is depleted. This means the card does not necessarily have to be spent on only one flight.
If the price of the flight exceeds the gift’s value, you’ll simply be asked to pay for the difference.
Wingly gift cards are non-refundable. Once bought, the cards could only be used on our platform.
FYI - Flight vouchers do not make their money on flights that are completed, the main bulk of the revenue comes from vouchers that are forfeited due to expiring. Expired vouchers are normally honoured, but only after a reactivation fee is paid, which comes at a price well over inflation.