levels 1-11 (you get charm at 12
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The last time I bought a stack of tiny daggers it was sometime around level 18-20, and now at level 59 I still have something like 6 left from the same stack. However the very few times I've used the pet I was happy to have it. I think the majority got used farming shadowed men for essences. One time I used it to kill a named I was farming because it was more powerful than the surrounding charmable targets.
Not me personally, but back when I played a paladin in the mid 30's I duoed with a chanter who used it on the yetis in dreadlands because he was too low to reliably charm anything in zone. Of course if it were me now I'd just level somewhere else until I could!
Finally, I have summoned it once or twice on raid targets where there was nothing to charm because why not.
-Propo Fol