Once your creatures are out of the way, Ajani, the Great Hearted has no way to protect himself nor provide you with any advantage for having him on the battlefield
However, I think the bigger opportunity is that this feels like the core to a strong Boros aggro deck: Particularly with all the Heroic+Valiant in Boros
When we target one of our other creatures with a pump spell or a protection spell we get a free poison counter, if our opponent tries to kill our creatures with targeted removal we get a free poison counter, and there are even some strange combo possibilities in Infect itself, especially with Spellskite
Unfortunately, this effect doesnt come cheap, as youll have to pay two mana for each card drawn this way
Whenever you create a Treasure token, you will get an addition one as well