The Apple Watch includes a built-in lithium polymer battery (a few hundred mAh; slightly more than 3.75 V) which is recharged using a wireless inductive charging cable. The cable does use magnets to attach to the back of the watch; but the charging is still done wirelessly.
Andreas Ødegård points out in a 2013 article on the Pocketables website that:
- Wireless charging is slow.
- Waterproofing a micro-USB jack is hard to do, especially on a tiny watch.
- The Pebble smartwatch "has its own proprietary connector. It’s a mix between a pogo pin connector and a magnetic connector, using two magnets on the side of a pogo pin connector to provide charging."
- The Pebble watch's connector is better than a wireless one: it gives you the high speed of wired charging, is durable, and is waterproof.
It does seem possible to charge the Apple Watch faster by gaining access to its concealed "diagnostic port". But some disassembly may be required. Also, once you remove the diagnostic port cover, the watch might no longer be waterproof at all. And, I don't know enough about electronics to say whether or not such faster charging could possibly damage the battery or cause other problems.
Why does the Apple Watch use wireless charging instead of a magnetic wired charging connector?
Note: It's definitely not a patent issue, since Apple themselves are the owner of the MagSafe power connector patent.