You use the wildcard to tell eigrp which interfaces its running on , eigrp by default summarizes at classful boundary , if you want to specify specific interfaces you would be more granular with your wildcards
, theres no diff in what you have specified above , if you had 172.18.1.0 /24 and 172.18.65.0/24 on 2 interfaces but used that 172.16.0.0 it sees both as eigrp once auto-summary is enabled , but usually you would be more granular and specify both interfaces under the network statement to be sure thats only whats used in eigrp and not all interface that fall under that subnet mask
