Accepting a dispute signals that you do not intend to challenge it. On a technical level, it is not dissimilar to doing nothing and simply refraining from submitting evidence. Accepting a dispute might speed up the closure of the dispute from the cardholder perspective, but there is no guarantee of this and no way to predict whether this will be the case with any given issuer.
Operationally, accepting a dispute can be helpful to signal to yourself and to other users on your account that you have already reviewed a dispute and decided not to challenge it.
No. Accepting effectively speeds up the dispute being marked as lost but is otherwise no different to any other lost dispute.
Accepting a dispute will immediately close the dispute as lost in your Stripe account.
It might, but you shouldn't assume that it will. In any dispute, the question of when funds are returned to the cardholder is up to the card issuer and their own handling of the dispute process.
Whether you accept the dispute or challenge it and lose, it's up to the issuer to decide when they will return funds to their cardholder. Your acceptance may or may not influence this.
See: When a customer disputes a payment, when will they get the funds back?
No. Acceptance is irreversible. The card network will no longer accept evidence for this dispute.
Yes. From the card network perspective, an accepted dispute is just like any other dispute, and still counts against your dispute rate. The dispute is not erased or annulled in any way.