XMP writeback workflow disabling impact

Can anybody hlp in understanding what are processing profiles and use the use of XMP writeback workflow? Why do we need this workflow? Can I disable it compeletely or for a path, say /content/dam(?!/XXXX/us/en/documents)(/.*)/jcr:content/metadata? what are the implications? This workflow also updates last modified date, so wont that conflict with other workflow named DAM Set last modified date? ANy detailed explanation fothese workflows is appreciated?