Than what does ARP->Make Static does ?
When IP device wants to communicate with another IP device over ethernet (or wifi), it sends packets to MAC address. ARP is protocol suite to map IP addresses to MAC addresses. And when device resolves MAC address for connection peer, it temporarily stores the MAC address in ARP table so that it doesn't have to resolve it for each individual packet. ARP table entries time-out in configured time, Mikrotik's default seems to be 30 seconds, other vendors may have it much longer (can be in order of hour).
If ARP resolution procedures are not successfull (e.g. because broadcasts are blocked network-wide or some otger reason), then it's possible to add static entries to ARP table (which don't get timed-out). This should be used carefully because things will break if for any reason mapping between IP and MAC addresses change (e.g. because host gets NIC replaced).