To concede or not is irrelevant from a legal process point of view. There are certain steps that are required a part of the process of the electoral college. Those steps will be conducted regardless of the Presidents statements.
HOWEVER
To not concede is also important as some of those steps require actions by 3rd parties. By not conceding, the President is asserting that he wants to continue the fight and signals to those 3rd parties, that actions taken on his behalf are welcome.
Specifically, a Senator and a Representative is required to contest the vote in writing. I believe this signals, along with the Jan 6th rally in DC, that there is still a fight and that the action or inaction of Congress will be recorded for history. Further, that those actions will weigh heavily in the next election. Some have already chosen to publicly support fraud. They will be remembered.
So it only takes one Senator and one Representative and after debate it automatically goes to the House?
Some have already chosen to publicly support fraud. They will be remembered.
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Conceding the results of a fraudulent, stolen election outcome would not only be illogical, it would be dishonest and therefore immoral. And that holds true for everyone, not only for the candidate who was victimized by the fraud.