The ancient/classical era value sea routes within civs are overtuned. In the midgame though, I definitely can see the high risk high reward of the sea routes tuned up and working as advertised. I just had a Venice game where the sea routes were extremely lucrative but getting plundered frequently, and the land routes held rocksteady all game long. Backstabs are the worst, I lost god knows how much gold in the renaissance to Wu. After that I had caravels watching the full length of supply lines but missionaries were still trickling in and pick off 2 or 3 routes a go before the caravels could scout them and take them down. Once I started pulling frigates off the front lines for backwater supply line duty, I understood why the sea lines offer such lucrative rewards.
But in the early game, deep within your own borders, a close sea route of only a few tiles kinda lets you work every mine and hammer out all the things.and is trivial to protect, and yeah, it gets kinda silly without the downside.
But in the early game, deep within your own borders, a close sea route of only a few tiles kinda lets you work every mine and hammer out all the things.and is trivial to protect, and yeah, it gets kinda silly without the downside.