In my experience this only lasts for the initial arc at best and then the protagonist becomes fully integrated in the world and is no different than someone already living there, with all subsequent arcs receiving no benefit from having someone from another world. The vast majority of isekai make no effort to integrate the protagonist's experience from another world into the plot and instead rush to sweep it under the rug.
There are of course exceptions to the rule but the vast majority of isekai I come across is as I described above.