Why are banks canceling Zelle?

AMARILLO National Association National Bank 18 American National Bank 6 Bank Iowa 4 BMW Bank OF NORTH AMER 28 Dewey Bank 3 FIRST INTERNET Bank IN 13 First National Bank in Tremont 4 First National Bank of Kansas 1 First National Bank, Taylorville 12 First NM Bank 7 First State Bank of Bigfork 3 Geo. D. Warthen Bank 13 Keystone Savings Bank 10 LYONS National Association National Bank 4 MINNWEST Bank 12 Poca Valley Bank 5 STOCK YARDS B&TC 13 Sundown State Bank 4 United Farmers State Bank 1 WINTRUST Bank National Association 10