While many longtime fans might prefer Blizzard stick to their PC roots, it should hardly be a surprise that they want to push further into the mobile market, especially given the success of Hearthstone. That said, the mobile gaming market has grown into a massive industry, with the gaming market intelligence website Newzoo reporting revenue from mobile titles accounting for $63.2 billion, or 47% of all gaming in 2018, and further projects it to grow to over $100 billion by 2021. Critiques of the mobile game itself have been mixed, but much less severe, though it's been made clear that Immortal simply wasn't what fans were hoping for.
While Diablo: Immortal had a harsh reception at BlizzCon, the criticism has so far largely revolved around the reveal itself, and the lack of accompanying Diablo 4 news or content updates for Diablo 3 (although there was later controversy over whether a Diablo 4 announcement had in fact been planned).
The press conference closed be stating that the main reason for developing Diablo: Immortal to mobile was to introduce the game to a much broader audience, and that there were still teams working on multiple Diablo projects for the diehard PC fans, so it can be assumed that any future mobile development would have similar goals - not that those projects should replace the current game series or discontinue support on current platforms, but to enhance their reach around the world. They went on to speak on the convergence of mobile, PC, and console gaming (as we've seen with games like Hearthstone), and how the level of fidelity in mobile devices has improved to the point where the quality can be similar to that of PC and console. I will say also that we have more new products in development today at Blizzard than we've ever had in our history and our future is very bright." Some of them are with external partners, like Diablo: Immortal many of them are being developed internally only, and we'll have information to share on those in the future. "In terms of Blizzard's approach to mobile gaming, many of us over the last few years have shifted from playing primarily desktop to playing many hours on mobile, and we have many of our best developers now working on new mobile titles across all of our IPs.