Delete conversations means delete, not hide!
So, the way that I have found this to work is that when I actually want to DELETE a conversation, somehow, after some time, it pops back again. That is not what should happen. I want to be able to get rid of conversations that are no longer of use for me, or I just don't want to remember some, or whatever reason.
Add this option and, among a few others that should be there by default, at least on a PC (yeah, you got me, I mean KEY SHORTCUTS) and I most definitely guarantee to you that users will be more than happy!
Remember. DELETE = GONE, BYE, ADIOS! We should at least have this option working this way. For the sake of our privacy, I could say.