I have a Tag watch I bought 5-6 years ago for around $2500. If I sold it, I could probably get roughly $1500 for it now as its in near mint condition. An Apple watch with a degenerating battery that will be obsolete within 2 years will lose 95% of its value in 5 years.
I seriously don't understand the purpose of the Apple Watch...and I've owned 6 Macs, 4 Apple TVs, 7 iPhones, 5 iPods and 5 iPads.
I'd be awfully surprised if the battery couldn't be replaced. (Not by the user.)
The existence of the gold Apple Watch has also got me thinking if Apple isn't planning on supporting updating the internals of the Apple Watch as well. That is, a gold Apple Watch could be updated to v2 and v3 of the SOC (and perhaps the display as well).