Across the globe, more people now use mobile devices as their primary means of obtaining information and requesting services over the Internet.
Why Mobile devices you need to use to get Mainframe data.
This shift is due to the convenience of being able to carry devices wherever they go, along with their user-friendly and intuitive nature. Mobile application users expect access to accurate and up-to-date information, not time-delayed copies.
This requires mobile applications to access and interact with the systems of record in the enterprise.
This crucial shift has motivated enterprises to develop mobile channels for their existing business applications and to plan for new kinds of applications that can exploit the unique characteristics of mobile devices.
Enterprises have already made large investments in information technology systems and cannot afford to recreate these investments just to enable a new channel to their intended audience. Read further in this link from IBM.
Also read this how to access mainframe data into Mobile