IT departments often provision all users identically, across many different roles. That consistency makes things so much easier -- for IT. For the users themselves, not so much. It's no wonder, then, that users who want to be efficient and do their jobs well often find ways to supplement the tools IT gives them with apps and devices of their own choosing.
It makes sense. Consider a different kind of workplace. A mechanic who regularly works on Fords will have some tools in common with one who works primarily on Mercedes, but much of what is in their toolboxes will be different. Each make of car requires special tools, and without them, a mechanic will either not be able to complete the work properly or will have to waste hours improvising with a workaround. Repair shops invest in specialized tools because they know that time is money in their business and that shoddy work leads to unhappy customers.
And yet enterprises still hand every employee a corporate PC, or a thin client with a server-hosted virtual desktop (also commonly known as VDI), with the same set of tools for everyone. It's not surprising then that only 15% of employees say that they are completely satisfied with their technology management department's understanding of what they need to be successful. For the remaining 85%, there is a gap -- a big one that they will increasingly close with their own devices and apps.