Asunder seems to say phylacteries are in fact blood magic. Evangeline muses on how it's "a bit of hypocrisy" the Templars allow since it makes their jobs easier.
From Witch Hunt:
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Finn: If the elves concealed the relics with magic, only the blood of their kin will reveal them. Ariane.. we need your blood.
Ariane: What? Why me? The Warden’s Dalish too! (If the Warden is Dalish)
Finn: Grey Warden blood is.. different. It wouldn’t work. It has to be you, Ariane.
Warden: Is this blood magic?
Finn: Um.. blood doesn’t power the spell – it’s just a component. It’s.. certainly a grey area, so let’s just keep this between the three of us, shall we?
Dog: (barks)
Finn: Four of us.
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There is clearly a kind of magic that one learns from demons* and which requires the caster to draw power from life force/blood (their own or someone else's). The Chantry forbids this kind of magic and calls those who practice it maleficar.
There is also clearly a kind of magic that uses blood as a component in spells. One does not have to talk to a demon to learn or cast these spells, and the spells are powered by mana (and possibly augmented with lyrium). The Chantry does not forbid this kind of magic, and in fact employs it. However, the close proximity of "blood" to "magic" is enough to make otherwise upstanding Circle mages nervous about doing it, and to get templars thinking about hypocrisy.
I can light a bunch of hickory wood on fire and cook food. That's your standard blood magic. I can light a bunch of charcoal on fire and cook food. That's your standard mana-based magic. I can light a bunch of charcoal on fire and scatter hickory chips on it to hickory-smoke something. That's your grey area. I'm cooking with the charcoal, but using a small amount of hickory to explicitly get hickory flavors in my food. So do I say I'm cooking with wood, with charcoal, or give it a new name?
*I've heard it argued that Jowan may have learned blood magic from the books removed from the library and taken to Irving's office. I think the weight of the in-game evidence is on direct demonic involvement being necessary, but I see where the inference is coming from.
...and now I want to go look for barbeque...