It could be interesting either, as Bob suggests, being an optional extra or with some element of flexibility built into it.
I, for example, live on the Isle of Wight and for any trip there is the challenge of the Solent to cross each way. It is my choice to live there and am not complaining but I invariably have to factor in the cost of a hotel at the start or end of a trip depending on flight times.
If you get a sea mist etc then this can seriously disrupt the crossing, which stops overnight, so if an early morning crossing is delayed the knock on effect can be a missed flight. Safer therefore to travel to the airport the day before.
Coming back then a delayed flight, baggage delay etc etc could mean that you can't get back before the last crossing of the evening. Safer then to book a hotel & travel back next day.
I am sure there are others with similar timing issues so if there were flexibility to take this into account it would certainly be something to consider.
I did book a taxi from Southampton to Heathrow & back a couple of years ago when I had just recovered from a broken shoulder & did not want to risk further injury. Much more pleasant than the train or coach but it was at a price...