Why are pole vault indoor records better than outdoor's?

Question

In September 2020, Duplantis beated the world's pole vault record with a 6,15m jump. World Athletics mentioned Duplantis scales 6.15m in Rome, world's highest ever outdoor vault, where I find the reference:

*Note: In 1998, the IAAF decided to accept indoor world records as the official world records if they were better than the best outdoor mark.

Back in Feb 15, 2020, Duplantis had jumped over 6,18m in Glasgow, in what is the current Pole vault indoor world record.

So my questions are:

• What is the reasoning behind the IAAF accepting indoor world records as the official world records if the improve the outdoor?
• How is this treated? Do they keep an indoor, outdoor and generic list of records?
• Why is that pole vault indoor records tend to be better than outdoor's?

Note I am aware of the question Indoor / outdoor track and field different records? but I am looking for information specific to pole vault, not the rest (which was kept unanswered there)

Answer 1

I'm afraid I can only provide educated guesses.

• In all running events the indoor athletes are handicapped by the tighter bends. 200 meter dash is hit the most because there is a huge difference between the lanes. Some events cannot be done at all. Some would benefit from having wind from some direction. Anyway, it sure makes sense to maintain separate records for such reasons.
• I don't know why this rule was changed. May be they determined that indoor events didn't enjoy a particular advantage in any event? Sure we may have a special indoor arena where coincidental structural feature may give something. I have heard/seen speculations of some long jumpers getting extra distance as the area near the take off board was essentially a spring board.
• About pole vault in particular. Lack of wind prevents taking advantage of a favorable wind (again giving outdoor athletes a better change at the WR), so it makes sense in a sense to include an indoor WR. But, pole vault is extremely sensitive to disturbances, and the slightest change in the wind may throw the jumper off a critical inch or two from their ideal spot. So here indoor conditions may be better because the wind is totally predictable.