Difference in working between unpersist and unpersist(blocking: boolean)

Question

I am working on an attribution report and i am caching the dataframe since it is being used frequently in the later stage of the code. Once the usage is done, should i unpersist() or unpersist(true). I understand the basic difference would be async and sync respectively. But does one have more latency than the other? Or is there any other implications to it?

val dfForWeb = loadData(aggregationType, readConfigForWeb).cache()
//some logical code blocks
..
..
..
dfForWeb.unpersist() //This works fine

//Tried using the below and got the same result:

//dfForWeb.unpersist(true) --This also works fine

The actual code is as follows:

val dfForWeb = loadData(aggregationType, readConfigForWeb).cache()
val dfForMobile = loadData(aggregationType, readConfigForMobile).cache()
if (condition) {
  for (item <- GeoAggregationList) {
    processData(dfForWeb) //This dataframe is used for a lot of computations later
  }
} else {
  processData(dfForWeb) //This dataframe is used for a lot of computations later
}
dfForWeb.unpersist()
dfForMobile.unpersist()

I am trying to be cautious as this application needs to be scaled and when the actual data is processed, i am doubtful if unpersist() and unpersist(true) would make a huge difference in terms on latency and data loss. Please advise.