One thing I think is worth remembering is that a lot of the characters we see in worm meet the bar to become a heroic spirit, simply because worm spends a lot of time focusing on the big, world ending stuff. What we see is also likely to be focused on more in the public conscious, with things like the behemoth video causing a lot of people who otherwise would have not made the cut getting into the throne simple because they were a part of something the vast majority of humans on at least two earths saw and likely passed down.
While I don't know if Taylor would actually mention it, their biggest mistake was actually doing the reverse and trying to burn down the building. While not something that should normally be done, given the stakes they are under their best option was to at least attempt to destroy the caster's lair instead of waltzing in.
The whole chapter kind of reminded me that for all that berserker would likely be her best class as a servant, Taylor fights like a magus and hilariously enough actually meets the conditions to be summoned as a grand caster.
