What is the difference between 'By State' and 'Sequential' tabs, why do they display the same data

The ‘By State’ tab will track how many times the record moved to that state and groups by state and On selecting 'By Sequence' gives the details about the actions performed on the item are sorted chronologically.

The By Sequential view is the default view, unless the item moved back to the previous states the 'By State' tab won't get displayed.