For the record, the Pro version is now "on sale" for $4.99 USD. The price was doubled, and then cut in half to coincide with ads in the message list.
That happened with the last 1-2 hours. I looked earlier, after you posted $9.99 price, and it was at that, for both "Pro", and "in-app purchase" for the free version.
A clever way to nudge people who don't want to see ads into buying this app...
... it would've been if only that change were announced clearly, without being sneaked in.
You have to ask, why should this product be any different?
Despite the life-induced cynicism and skepticism, I have a hope for the best in humans, until proven otherwise. But after the past year of continuously lowered bar for acceptable public behavior and business ethics, I am no longer shocked: this is just yet another "illusion" to disappear.