That rule allows only tcp/80 connections and no matter if they were dstnatted or not. The universal “allow all forwarded ports” rule is:
/ip firewall filter
add action=accept chain=forward connection-nat-state=dstnat
What exactly you don’t like about this universal rule? It only allows traffic which was forwarded using dstnat rule, it does not open your firewall in uncontrolled way. It’s actually safer than the rule you posted. If there was an evil hacker in same subnet as your WAN, your rule would allow him to access port 80 on any address in your LAN, while the universal rule would allow access to only one address where your dstnat rule forwards packets.