[whafro]

They may require more maintenance, but that maintenance may also be lighter.

You could also argue that this type of construction allows more room for generational upgrades than those expected to last 500 years.

Integrating PV solar into the roof might be a more reasonable proposition if you know you're planning to replace the roof in a few years. If you don't expect to have to replace it for several more decades, you're less likely to make that investment.

This also applies to insulation, air sealing, electrical upgrades, etc.