I have one (Windmill lighter). Works wonderfully at sea level, and perhaps up to about 5k feet. At high altitudes it doesn't work at all. Worse than worthless, because one's lulled into thinking they have a working lighter, only to discover they instead have a useless lump of plastic. Disposable Bic flint lighters are much better.
Many piezo-ignited stoves will still work at altitude with *careful* monitoring of the gas flow: the higher the altitude, the less the fuel flow. The goal is to keep the fuel:air ratio between LEL and UEL (lower explosive limit/upper explosive limit). It's common to have too rich a mixture to light.
That said, some designs seem to work better than others, e.g., Primus are far more dependable sparkers than Markill.