In the first situation, if the Buyer breached the contract or walked from the deal, the Seller would get to keep the $10,000. It is the start of a suitable payment for tying up the home for a period of time, taking it off the active market and making plans for moving. In the second situation the Seller would get $500 for all the same consequences. Buyer could walk away from the transaction, for no reason at all, and only lose the $500 down.
When you go to sell your home and you meet with your realtor, pay careful attention to the listing agreement and to what you will and will not accept as terms of the contract. Get as much money up front as you can. It will keep the Buyer invested in the transaction and motivated to close. As it turns out, the $10,000 down payment only constituted 2% of the purchase price. Not a huge amount for a half a million dollar transaction. Protect yourself in the event of problem Buyers and know you’re compensated if the contract falls apart.