On Wednesday, November 13, 2019 at 9:15:53 AM UTC, Tanguy Ortolo wrote:

I have the impression that a flexible hose is
useful to avoid damaging the valve,

Of course it is: it frees two hands for holding the pump steading and operating it. A pump head you have to hold on the valve while steadying the pump with the same hand as the other hand pushes the handle is a recipe for damaging fragile Presta valves.

Andre Jute
Not approved by weight weenies