And what happens if ATC directs the airplane to hold on the runway for a few hours? The space shuttle used cryogenic fuel, and after loading they had to continuously replenish the liquid hydrogen due to leakage and evaporation for several hours until launch. That can work for a rocket with a huge operating budget on a dedicated pad but I don't see that working at a busy commercial airport.
Jet fuel is much more stable. It can sit in simple fuel tank for months with no special cooling or containment measures.
LH2 in tanks boils off and is vented. There will be different procedures for LH2 vehicles on hold than today. That might involve plugging in somewhere for active cooling while on hold. Or, it might just mean you load on enough LH2 to make up for losses while holding.
The practical merits of Jet-A fuel will be traded off against the value proposition of LH2 fuel. LH2 will win easily where volume is high and profits are greatest. So, marginal routes and uses will be the last to switch over.
The space shuttle, by the way, could not afford insulation on its external LH2 and LOX tank. We may assume that airliners' tanks will have vacuum- or aerogel-insulated tanks.
Jet fuel is much more stable. It can sit in simple fuel tank for months with no special cooling or containment measures.