Thaumaturgist Planar Cohort: better than regular cohort?

[ILM]

I'm reading the Thaumaturgist's Planar Cohort ability, and I feel like I'm missing something. Is there anything in that ability that couldn't be replicated by a well-placed Leadership feat? (assuming lenient DM)

[Psyren]

With a permissive DM there aren't many differences, since they can have an angel (or whatever) respond to your leadership call as easily as to planar ally if they want.

A big one mechanically is that Planar Cohort doesn't appear to care about your Leadership score - so if you have big negatives (e.g. low Cha, several cohorts died previously) you should still be able to get a max level planar cohort.