From Wikipedia:
In standard British English and Australian English, whilst, as a conjunction, is synonymous with although, whereas, but or while. Unlike whilst, while is also used as a noun (as in "rest for a while") or a verb (as in "while away the hours").The usage of whilst is chiefly British. For example, the BBC World Service website "Learning English", in their "Ask about English" section, uses the word whilst when explaining the usage of "while and whereas".
In American English, whilst is considered to be pretentious or archaic.
Looks like the writer is most probably British or Aussie.
Or me, big fan of 'whilst'.