The same reasoning does indeed apply to Garmin watches, smart fridges and car dashboards since people are only going to wear one watch and own one fridge and on

The same reasoning does indeed apply to Garmin watches, smart fridges and car dashboards since people are only going to wear one watch and own one fridge and one car. I don't see the downside of requiring everyone in your examples that already allows third party apps to do so for free (other than passing through payment processing fees) and without delay and censorship: the costs are minor or insignificant and can be included in the purchase price of the device. The advantage is that it leads to a fair playing field for app makers, lower prices for consumers (since the money that goes to the platform maker is all visible upfront in the device price and thus easier to compete on) and doesn't stifle niches that the platform owner doesn't like for whatever reason.