When to use film capacitor
All capacitors have their benefits/drawbacks depending on the application.

I've used Metalised polyester caps for high voltage/current resonant circuits for induction heating due to their low thermal drift coefficient and inherently high voltage rating. Ceramics are also good for this, however NP0 capacitors with nF ranges in suitable voltages are expensive. Metalised polyester caps are widley used in the AC/Mains arena due to those factors.

Electrolytics and Tantalums are great for high buffering storage requirements such as switchmode power supplies while augmented with some ceramics for nice current ripple performance.

Some age faster than others. They all have their application specific pros/cons.