Because you already do it!
Look around your organisation. Everywhere you will find intiatives of Visual Planning, Kanban style or Agile style planning efforts. Small whiteboards here and there, some structured, some not.
In your financial department, the accounting for your porjects are vital for invoicing clients or to depreciate your investments in product develpoment according to accounting and tax rules.
And – your collegues are tearing their hair off in efforts to keep up with the increased and required document needs in product, service and project deliveries!
In many organisations religion flourishes or different methods are á la mode. Of course it is good with some competition and some variation in your work. But is it efficient from a business point of perspective? Hardly.
I have the hypothesis that successful organisations manages to blend the visual way and the structured way-of-work in a unique mix, that will minimize double-efforts, over administration and to provide a unique taste of improvement success based on clear committments and responsibilities.
In too many customer PPM deployments over my 20 years as a consultant, we get too detailed. We override and overplan our competent coworkers.
As an example, by combining visual planning techniques with traditional time scheduling, we managed to take away the two lowest levels in the WBS and instead introduce self-committed cross-project delivery teams that ran Visual Planning Kanban boards successfully. PMs where really happy, teams where happy. Results showed they were on the right track!
So – do not hesitate to cut the crap and simplify by combining best of breed work-practices!

/Magnus Holmlid