Collections were marketed as a ground-breaking feature when launched, but it hasn't seen much development since and still feel like a half-baked version of bookmarks. I can't get much use out of it even after trying many times.
Using as reading list - It still only saves web links and not the offline text like the reading list feature in edge legacy.
Using as saved sessions - It works well but still takes two more clicks than edge legacy.
Using as repository of links - It doesn't have enough organizing tools as bookmarks, becomes cluttered very quickly, no sorting, can't move entries among different collections, can't archive items/collections like in pocket which is miles ahead in this use case.
There are some good things like attaching notes to a link, sync with mobile etc. but there are other better services in the market that don't try to be a jack of all trades.
Can you guys please tell how you want us to use collections, and what is the roadmap for future development.