> I know that my in-laws with a Tesla don't carry the key cards. They just use their phone
Are you actually sure you know that they don't carry the key card in their wallet? Why wouldn't they? I find this pretty doubtful, it just seems like a pointlessly unnecessary way to risk getting locked out of your vehicle if your phone happens to die or becomes otherwise incapacitated. What possible reason could anyone have for not just keeping the card in their wallet as instructed by Tesla associates upon receipt of the vehicle and the cards themselves? It just doesn't make sense.
Playing devil's advocate: what wallet? As more and more functionality is moved to the smartphone, the less reason to carry a wallet there is. A smartphone can already replace credit cards (Google Pay and similar), cash (several per-country payment systems, the one for my country will be released in a couple of months), and even the driving license! (https://play.google.com/store/apps/details?id=br.gov.serpro....)
In a more humorous note, I've seen many people use their cell phone as their wallet... by putting their identity card and cash inside the aftermarket cell phone cover on the back of the phone.
Over many years I have accidentally broken one card (I snapped it while using it as a scraper) and two have lost swipe and / or chip and pin functionality due to general wear and tear.
Are you actually sure you know that they don't carry the key card in their wallet? Why wouldn't they? I find this pretty doubtful, it just seems like a pointlessly unnecessary way to risk getting locked out of your vehicle if your phone happens to die or becomes otherwise incapacitated. What possible reason could anyone have for not just keeping the card in their wallet as instructed by Tesla associates upon receipt of the vehicle and the cards themselves? It just doesn't make sense.