If Trump wins and Biden doesn't concede, they will still pay out. I agree they shouldn't have that included in the requirements, or at least worded that way - but I don't blame them for wanting to cover all their bases in case America finds itself in a constitutional crisis.
As I mentioned towards the end we would be using "logic and reasonability" to determine the outcome so I could not imagine a scenario where trump won electoral college and we wouldn't pay out. That being said in my opinion it is hyper unlikely that trump will hit 270 electoral college votes without a re-vote or something major happening but stranger things have happened.