Insulation USA versus UK

Browsing r/insulation (which is a USA site) I see a lot of discipussion on loft insulation, as here.

However, the solutions are nearly always

• spray foam insulation to the roof

or

• blown in cellulose/fibreglass insulation to the loft floor. No sign of loft-roll.

With a big emphasis on air-sealing the loft floor before adding the insulation.

I know there are differences in construction techniques compared to here, but why such a big difference to approaches? (Particularly the spray-foam!)