I'm glad you didn't say it was better, as I've just bought a 720!
I find this geometry thing a bit puzzling. I also have a Triban 500SE which I was going to say was similar to your CF Triban, but it looks like the head tube is shorter on the CF Triban. Anyway, the
Decathlon write ups claim that the Triban is for commuting and training rides and the Ultra has a more racier geometry. However, by measuring the reach and stack from the bottom bracket the two bikes are practically identical. So it appears, to me anyway, that the more expensive B'Twins are marketed by claiming they have a racier geometry and the lower cost Tribans are marketed as starter road bikes / commuters with a more leisure geometry, when there is no real difference. I may of course be missing a point or two, so I would be interested in peoples views, even if it just stops me starting a new thread!