Under that lens, the clocks were very effective. We rarely ventured further than 1 week away from our capital. Rarely interacted with any urban area, since the only city was 8 days away.
Unfortunately, since this was a sandbox, the areas around our city were strictly low level, and we were already overleveled for them.
The point is: it isn’t sufficient to incentivize a certain playstyle, the implementation needs to work. In particular, you need to be aware that the structure you create can incentivize the party to do that, regardless of the fact that you want them to do other things as well.