Often those SMEs are data folks, and if they are allowed to develop in $TOOL_DU_JOUR, and that app becomes business critical, the IT folks will be stuck supporting it. And if that thing doesn't become well supported, or it isn't easy to find someone who can support it, that's a problem.
I've run into this quite a bit at my workplace. Some business group writes an app in Excel using VBA + an add-in and it becomes the core part of some workflow. But IT didn't know about it, nor did they know about the (for example) 32-bit ancient Excel add-in that it requires, which then breaks when an Office upgrade happens...
Now IT is stuck where a routine upgrade broke some weird edge case thing and needs to maintain a downlevel version of Office for a small group until they can re-develop their business-critical tool in something else.
Use-known-stuff rules up front -- in this case which may well be VBA -- alleviate a lot of these long-term problems.
I've run into this quite a bit at my workplace. Some business group writes an app in Excel using VBA + an add-in and it becomes the core part of some workflow. But IT didn't know about it, nor did they know about the (for example) 32-bit ancient Excel add-in that it requires, which then breaks when an Office upgrade happens...
Now IT is stuck where a routine upgrade broke some weird edge case thing and needs to maintain a downlevel version of Office for a small group until they can re-develop their business-critical tool in something else.
Use-known-stuff rules up front -- in this case which may well be VBA -- alleviate a lot of these long-term problems.