I think they go together, Acquire physical resources may need to conduct procurement processes as you may not have them available. Usually, you can not get these resources and expense them yourself as most companies would have rules established to prevent.
The best reason I can think to justify this is: CAPEX vs OPEX, if it's officially procured, physical resource, it may be seen as CAPEX. In contrast, If you buy this and expense it will definitely be seen as an operations expense