This product seems to me fatally flawed in many ways. First of all, there is very little new about it. It's email searching - nice, but searching email is something I do once in a while, and when I need to do it I can usually wait till I can log into gmail or put on my outlook client.
Secondly, what's with the price? This is offered for free everwhere, and it's not a constant problem I always have. Actually, I cannot ever remember a time when I really needed this, and I'm not going to shell out $4 EVERY month for something that I may require twice a year. If it were an app you pay $1,99 for and forget about it till you need it, I would probably buy it, but not a $4 subscription every month.
And furthermore, the platform already comes with an email client - they could add the search thing anytime, effectively ending the business. I don't like the product as a consumer, and it seems poor to me as a business too.