Remember that banks are a business first, they exist to make money. They make money by providing selected services to paying customers.
They make no money on selling you coin at face value nor do they make money by buying it back from you at face value.
Many banks will provide coin to customers in reasonable amounts and accept returned coins, again in reasonable amounts. They are in no way obligated to do either, especially for individual customers.
If you are one of their business customers they will almost always provide rolled or bagged coin upon request but larger quantities may require prior notice.
If a bank graciously provides you with boxes or bags of coin for face value take it as a gift and return the favor. Dump elsewhere for sure. Be nice to the staff at both the source and the dump banks. Small tokens for repeated favors go a long way. A box of donuts will get you remembered and they may just set something aside for you when you come in the next time.
While one way for the bank to make money is to be nice to the customer, individuals are rarely the big rainmakers. You will always do better if you have accounts at the source and dump banks. Keep track of which branches still have customer counters (less and less do these days).
Consider an account at a credit union, they often have coin counters and are often more agreeable to accept large coin deposits with them. They are also less driven by the profit motive so tend to be more service oriented. Just remember to not burn your bridges. The quickest way to get a coin counter removed from your local facility is to dump tons of coins there all the time. Spread the wealth...