Re: Good, good.
"A carte de sejour doesn't secure status. Rather the reverse, it's proof that you have secure status as an EU citizen and largely fulfils the place held by an ID card for a French citizen."
I'm largely agreeing with that. The government website also explicitly states that it is not needed.
It's for non-EU citizens that they're really useful.
"It's supposed to be renewed every 10 years anyway."
Note quite. There are /plenty/ of different kinds of carte de séjour, and those for EU citizens coming to France to work are limited to the duration of the contract + 6 months, to a maximum of 5 years. It doesn't seem worth the bother (which can be rather huge, depending on the préfecture) unless one really wants a French ID.
https://www.service-public.fr/particuliers/vosdroits/N110