Having your own cable for AC (here it's Type 2) is the norm in Europe, so I'd say it's survivable.
And now every EV needs to have a different charge port configuration for North America vs Europe, and North America is stuck with NACS. (NACS is fine for DC but still sucks for AC. It cannot support 3-phase charging (which I admit has always seemed like a silly feature except in the limited case of 1 or 2 chargers in a single family residence), and cables and adapters cannot passively report their current rating. So you would need to build a kind of gnarly active MITM system to make a safe extension cable, whereas a Type 2 to Type 2 cable is built part of the Type 2 design.
Later, Tesla proved the whole thing pointless by successfully fitting Type 2 in the same location…
When Tesla later engineered the European Model S, it needed three-phase AC and adopted a modified Type 2 connector, which fitted behind essentially the same tail light door.
But that’s all history now.
Arguably both markets ended up with good solutions for their needs: NACS is exceptionally compact and well suited to North American single-phase AC plus DC fast charging, while Type 2 is larger but supports Europe’s widespread three-phase AC.
Only because everyone aimed too low. NACS (as mentioned before) doesn’t cleanly support adapters or detachable cables. And CCS Combo 2 is unnecessarily clunky. And you end up in a rather awkward position if you ship a car from the EU to North America or vice versa.
It ought to be entirely straightforward to design a standardized cable, NACS at one end and with a new interface at the other, that can attach and detach from a compact and weather resistant charge port. It would be fully compatible with all NACS vehicles, and it would achieve this by negotiating voltage and current limits with the EVSE at the other (newly specified) end.
It could even be cheap in a low-current version — it would basically be an extension cord, with two 12AWG hots and a ground plus a couple of little wires and the whatever inexpensive electrical parts are needed to declare its capabilities. If you can buy an e-marked USB-C cable for a few dollars, the latter won’t cost much.
Shipping a car between the USA and Europe is an extreme edge case for wealthy people and the marketplace can solve for the issue of adapters and dongles where the need arises.
(For reference, I'm in a CCS2 marketplace.)
Means existing chademo cars will have less value as time goes on.
Well, 3phase is more efficient as you have less losses in the cabling.
May save you 5-10% on the bill.
There is a savings over the system in which you use 2 of 3 phases, which gives unbalanced phase angles. And that system is widely used in the US in non-single-family installations. But if you have a bunch of chargers, you put 1/3 of them on each of the pairs of phases, and everything balances back out at the panel whenever a decent number of chargers are in use.
Maybe, if a a car could rely on having 3 phases, it could avoid some ripple filtering by taking advantage of constant supply power (no 2f component), but cars need to be able to charge from a single phase even in Europe.
US power supplies tend to be 1kW though for constant load (1.5kW rather than 2kW) so even worse.