> What difference does it make to the seller if its a all-cash?
A mortgage requires approval by the lender after the terms are settled with regard to the particular property (often including a third-party appraisal by someone approved by the lender to validate that the value of the property, rather than merely the sale price, has the correct relationship to the loan value), which means that an offer contingent on a mortgage can fail, whereas an "I have cash right here to pay now" offer cannot fail.
A mortgage requires approval by the lender after the terms are settled with regard to the particular property (often including a third-party appraisal by someone approved by the lender to validate that the value of the property, rather than merely the sale price, has the correct relationship to the loan value), which means that an offer contingent on a mortgage can fail, whereas an "I have cash right here to pay now" offer cannot fail.