You are still. If you go full CON to achieve that kind of damage with Blood Curse, your other skills are gonna suck hard. Notice that Blood Sucking in that video was only doing 900 damage per tick (probably level 1 but still). Not to mention your other alternatives are all single target skills that will never manage to kill groups of monsters without JP.
That video was actually posted as part of a solo grinding guide for FF C2, but the comments instead pointed out that using the usual JP + HK + BB/MM rotation would have been faster. The skill was, like Blood Bath, intended to be a party off-healing skill, but IMC as usual had to ■■■■ up with non-scaling bullshit and more generally not knowing how much health people can achieve endgame.
For me FF C2 only brings another reliable, low CD dps skill in the form of Kundela Slash, and that’s about it. If I ever pick up this game again I will only put 1 point in both Levitation and Blood Curse for utility.