Either product can be used separately. I use the Dicor product for all my vent, skylight, stink pipe, etc., caulking touchup when required (check spring/fall)....., easy to use. In the event I have to replace any vents, skylight, etc., the Dicor is easier to work with then removing the Eternabond sealer tape.
However, I have applied the Enternabond sealer tape on my TT's front cap/roof seam and slide roof seam joint in lieu of the Dicor touchup...., I applied the Eternabond right over the existing OEM caulk. The Eternabond solution will last longer and doesn't require any PM.
My Eternabond application: Post #8 & #58 here:
I do keep some spare Eternabond in my TT for those 'just-in-case' emergency EPDM roof repairs.
2016 GM 2500HD 6.0L/4.10
2018 Jay Flight 24RBS
2002 GM 2500HD 6.0L/4:10 (retired)
2005 Jayco Eagle 278FBS (retired)
1999 Jayco Eagle 246FB (retired)
Reese HP Dual Cam (integrated sway control)