This is from a Gartner report that I found a few weeks ago.
For me I only focus on two aspects. The first one is that I work with my vendors to create positive outcomes. The second one is that I do what ever it takes to reduce rogue spending.
The question I have for you is simple. Do you really know what all of your various departments are spending? Is there a better and more efficient way? Procure to pay is not the panacea (cure all). It is simply a tool.
What works best is to do a discovery session. Learn, adapt and change based on what you have learnt.