The 3 up front makes capacity go faster but it’s still the same number of lightning lanes available per day per ride.
I assume some level of unused with Genie+ too. You couldn’t pick return time so people may have booked a time they couldn’t use but held it hoping to modify later. Same as booking times at end of day and then leaving before the time was up. I agree that under the new system people could walk away with 3 unused in hand. One benefit of that if it turns out to be widespread will be less people using the lightning lane entrance so shorter standby lines, especially towards the end of the day. There’s always a silver lining