From the TGS live part1 translation
f; ok next healer
f; well for low level we only have conjurer
y; there isn’t much arcanist healers as it’s harder to play
y; but as you level as scholar you’ll be able to heal really good
It's not that it's that much harder to heal as an arcanist, it's that you classify them as DPS on the dungeon finder! At lower levels the majority just uses the DF to get parties and get stuck because there is an overabundance of DPS.