Thank you for taking the time to share your experience !
Very interesting to see this hotel, not on my usual route, but much appreciated for gaining insights.

Yes, the no self service policy of alcohol could be subject to a local/regional/national law,
or if there a minors present.....
was there no menu of what choices / brands were served?
or the bean counters are on standby for an adminstrative hassle.....
one can serve any type of beer / wine of any brand....
and cost effective for the accounting department which might be why you have to sign the bill (+carbon copies)

The coffee/tea + soft drinks to be served is usually lauded by bloggers because it orovides intimate personal restaurant style service ....
Or at least keeps the buffet area neat and tidy without being lived in by monkeys ....
I do find personally it is nice to help oneselves to non alchoholic drinks but i think it will wreak havoc on their accounting department

Enjoy your stay and will update the wiki accordingly, thanks again for sharing