Well that's because this is checking if a value may be a valid number.
It's not safely converting the value to a number.
That's done after a parseFloat()
And this is the reason why Google is that worried about 'european privacy'.
Being less reliant on american companies is not that bad for the rest of the world.
Problem is quite a few european countries right now don't trust american companies anymore so they are working on their own mail service, cloud, network and hardware components, ... (you know if american companies agreed with american government to spy on us they kinda deserve a nice fk off).
So who is damaged by this european behaviour? American companies.
And now Google is suddenly concerned about our privacy.