FortiGate Cloud for SDWAN

I am researching FortiGate cloud and it seems built or marketed for SMBs and MSPs? At what scale do you think it won't fit? Do you think for a 100-site retail shop with a few zones at each branch I could manage this all from FortiGate cloud? Or would FortiManager be better? New to Fortinet so currently just looking at the solutions from a high level. Would love any experience input as well