From another site...
The Casio QL10 is a standard refillable lighter 4″ tall, with 4-function calculator, multi-alarm clock, two time zones and stopwatch. It lasted all of one season in Casio’s 1980 line and retailed for around $90 at the time and was dubbed a Calcu-Lighter by the press. Calculator makers pushed the envelope after perfecting miniaturization and the LCD display system, so it was only logical to package a lighter within a calculator during the pro-tobacco days of the 80's.
Reminds me of a story a very old physics teacher would tell us in HS. A mainframe computer was inexplicably crashing at seemingly random intervals. Turns out the hard drives of that time were not sealed, and the space between the heads and the disk surface was just wide enough for smoke particles to cause an error and crash in certain occasions. Some of the mainframe operators were smoking in the room and causing the crashes.
Not sure if it was just a cool story or a real thing, but based on his other stories it seemed pretty legit.