I think any reasonable interpretation of the comment you’re replying to is not “sleep is always good” but rather “sleep is good, on the whole”, which is absolutely true.
Both studies you linked indicate correlation not causation
Personally I use it more as a reminder than an official reference. So, for example, reminders of less common diagnoses or less common presentations of common diagnoses that I’ve learned and know but may not remember the details of but will come back to me with some prodding. If I actually need to dive deep, I usually use UpToDate
As a night shifter it’s completely life changing in allowing me to sleep comfortably during the day. 100% worth the price to me