It seems like a good way to use the posts. The marina calling the fishing dock a fishing dock may be a reason to not put cleats on it, possibly creating a trip hazard in a place where they are encouraging foot traffic. Most docks where you can keep a boat do not allow fishing from the dock.
I am a big fan of bungee lines for short term docking, you can toss one over a cleat, run to the other end and grab a regular line, pull some tension on the bungee, and tie the boat off, the bungee line will keep it tight to the dock. I bought 8 of the 4 footers at Gander Mountain when they cleared out the boating stuff at 80% off.
2006 Forester 19 Fish (new deck and carpet, Pontoonstuff interior, 2019)
1996 Mercury 50 ELPT4S
1983 Sea Nymph FM171 Striper (complete rebuild from hull up, 2014)
1985 Johnson 70 J70ELCO
Raystown Country, PA