Do you have that many false registrations?
My main problems are rather full mailboxes and invalid emails after a few years - even while the same users are active in the forum on a daily basis.
It is also a question of costs. With around 40 different forums, the solution of DragonByte mail is a costly element for me.
If I go that route longterm, it has to create additional value vs. this free addon.
Since several years I asked for throtteling as a new feature for DB Mail. Many people asked for it at Xenforo. But no progress in this direction. THAT would be an important feature for my use cases.
I can not see what kind of important features have been added over the last 3 years which would save me money, time or make daily task easier for me to keep my old users in the forum. If you pay almost 40 USD each year for this addon, I would expect more innovation and more open mind for user's suggestions.
History has shown that DB Mail is what it is and you can not expect that within the next 3 years important features for my use cases will be added. So why should I spend my money there?
There are other email options like Sendy or Andy's addons or phplist etc., which I could check again too.
I do not say that I will never give DB Mail a try again, but my past experience does not motivate me to try it out asap, if I am not forced to do it right now
Maybe new developers see this as an opportunity to offer better Newsletter addons at a reasonable price with a roadmap for features over the next 12 months. Or an app for Xenforo.... who knows...