It's typically not used in modern historical writing when referring to events located in areas that used the Julian calendar at that time.

But it is typically used when referring to events located in areas with no calendar system familiar to modern readers, most notably the Maya calendar. Maya Long Count dates are typically converted to the proleptic Gregorian calendar.

Also, many modern historical writings will display both Julian and Gregorian dates, particularly for dates around when the calendars were changing or when context is unclear (e.g. a historical figure who was born in an area with one calendar and died in an area with another calendar).