Don't, of course, know the full facts here - as greatorex points out, fuel could have been a signifcant concern.
However, to make comments such as "they landed safely didn't they?" betrays either a total lack of concern about flight safety generally or a total lack of knowledge of the dangers of CBs and thunderstorms. Getting struck by lightning is the least of your worries.
Severely unnerving the pax is not a good way to promote repeat bookings, either!