Most mortgage loan programs prohibit direct credits of cash from the seller to the buyer.
Most mortgage loan programs will allow the seller to assist the buyer with all or part of the closing costs.
Money is money, agreed, but in the world of mortgage loan underwriting they have to account for all sources and the buyer may only use their own cash for a down payment and so you have the restriction.
Most seller credits are for repairs. We suggest that you simply have the work done prior to closing.