Though in this case, it isn't even that so much as it's more a survivability argument (mobility) anyway.
Mobility isn't a matter of survivability except insofar as you'd die if you didn't have sufficient yalms-movement-within-X-seconds or you'd call all access to healing a matter of "survivability" (making the term ambiguous to point of near uselessness).
No mechanic requires an external buff increasing their mobility for players to survive. There are no raid mitigation tools that require immobility; even PoA can be flashed and every other ground-effect mitigation has room to dodge around mechanics present at the time those effects would see use. Every personal defensive is mobile. That leaves only whether a healer can produce sufficient healing while moving.
Again, I don't know why you're trying to sectionalize this into 'damage' and 'other' as if you're somehow taking the longer view here. Hell,
you have been the one most insistent on segregating a skill's net optimization in context from optimizing the skill itself (in DoT's case, by pruning the latter, thereby vastly simplifying the prior). Moreover, the distinction is moot; damage is the
only uncapped resource this game offers, by the simple fact that it doesn't have a single fight with objectives other than "Reduce X's HP to 0", while all secondary outputs (those which do not directly contribute to the fight's objectives) ultimately amount to DPS dealt (through opportunities enabled/preserved).