Is Dissipation really that bad?

[Dregenfox]

Well let's think about the total cost/benefits of dissipation. Fairy does 50'ish potency worth of heals per second, so over 30 seconds we lose 1200 worth of potency. We gain 3 lustrates which is 1800 potency, so a gain of 600 potency at the cost of the mana for a summon + swiftcast. Any Adlo's/physicks you cast from then on is just a straight 20% bonus for 30 seconds.

So..

basic cost of a dissipation is swiftcast+summon mana+GCD
basic benefit of dissipation is 600 potency + 20% increased healing for 30s.

What can we do with the GCD? Let say we use it on Adlo. Non-crit adlo is 600 pot for 1800 mana + GCD. Cross out the common factors (600 pot, mana, GCD) and we have the true opportunity cost:

600 mana + swiftcast CD. So it is pretty much equivalent to a 2nd largesse, more or less. As fancy as the skill is, it doesn't actually do anything - all it really does is let you trade one role skill for another.

--TL;DR - Dissipation basically lets you trade a swiftcast for a 2nd largesse that costs 600 mana and lasts 30s. I suppose the benefit is the flexibility it offers.