I live in California, USA, so naturally I'll reply.
Some general reasons
to purchase the Tesla CCS1 adapter (now):
- You frequently take trips (away from your home Level 2 charger) and need/want fast (DC) charging.
- Your trips can be away from the more well-trvelled areas and highways (where Superchargers are located).
- You are a person who needs/wants all the charging adapters (you believe in being prepared).
- You find that Superchargers are not always conveniently-located or immediately accessible everywhere you go.
- For whatever reason you favor third-party CCS charging stations (e.g., due to cost, reliability, location, amenities, etc.).
- You recognize that it's relatively easy and proven foolproof to purchase a CCS1 adapter (from South Korea).
- You worry that once Tesla releases the CCS1 adapter for sale on its North American websites, it could be sold-out for long periods of time.
- You've found J1772 (AC) and CHAdeMO (DC) charging stations to be too inadequate for your travel needs.
- For peace of mind (to counter "range-anxiety").
Some reasons
not to purchase the Tesla CCS1 adapter (now):
- Your car is not CCS-enabled.
- You do almost all your charging at home and Superchargers (or otherwise at non-CCS sites).
- You already have the (expensive, but slower) CHAdeMO adapter, and have found it adequate for your away-from-home DC-charging needs.
- Due to the added import duty/tax (in Canada).
- You anticipate that the Tesla price will be significantly lower (than the current ~$309[US]) when sold directly in North America.
- You worry that third-party charging sites can be more undependable than Superchargers.
From what I read, if a person stays close to home, major urban areas, and significant highway arteries, he or she may never really need a CCS1 adapter. Supercharging is probably adequate. However, this adapter is relatively small, well-made, and seemingly full-proof. If a driver can afford the cost, it is probably an attractive accessory to have in the trunk.