It's safe to be worn in the shower, that's enough for most people.
Edit: having looked into it a little more (not very knowledgeable about waterproofing, I dislike dive watches), there's no such thing as a "waterproof" watch, just a watch that is resistant to water at certain levels of water pressure. Information about it here: http://en.wikipedia.org/wiki/Water_Resistant_mark
There are touch screens that work when wet.[2]
[1] http://www.casio.com/products/Watches/Sports/ [2] https://www.youtube.com/watch?v=mVPku-xItv8
Addressing your second point, there certainly are touch screens that work whilst wet - however I suspect there will be significant draw-backs, such as responsiveness, colour clarity, etc. Again, I don't have the details but if Apple could make Apple Watch usable underwater without any compromise, I'm sure they would have.
However, it would have been interesting if they had released the "Sport" model as a bulkier, water-proof version, leaving the regular Apple Watch as the dress watch. There certainly could be interesting applications for divers, etc.
Edit: check out this review of the CAT phone you linked. http://www.cnet.com/uk/products/cat-b15/
"Very poor screen" and "The screen has been designed to operate when wet, too. You can't use it underwater, but it's fully functional when covered in flecks of water". As subnaught says, it's all about trade-offs.
I learned this the hard way when I got a new 30m watch for a sailing trip and it died the first time I stuck my hand in water. Timex even used to print something like that table in the paper that came with the watch. So I'll upgrade my "lies" characterization to "shameless lies".
(That said, I want Apple to do better, and I expect they will in the future. Underperforming on the first products would be a disaster. Better to under promise.)
http://www.techradar.com/au/news/wearables/apple-watch-is-sh...
Most water-resistant devices do not attempt this. You can put them under water, but if you bump them wrong you can ruin them.