Keep in mind that if you are an Outlook user, you have to first know VerbMAIL, exists, then go find, download, and install the plug-in, before you can use it. So 99.99999% of all Billion Outlook users will be unaware of the option until either it gets massive promotion, or MS decides to add it automatically in a product update package. Or they start receiving lots of VerbMAIL emails.
Let's hope the PRs are pushed by MS as well as Verb.