I have upvc windows with the typical handle with push button and lock which rotates ninety degrees to engage/disengage the locking mechanism (3 bolts in the bottom of the window frame which engage with plates along the sill).
What I can’t work out is the actual purpose of the embedded lock in the handle (with key). When locked, it prevents the handle being used, and this might be useful for security from the inside (eg if a toddler is roaming about) but it doesn’t seem to increase the security vs an attack from the outside.
Am I right or am I missing something? Insurance companies seem to require these locks, I think, which suggests they have some purpose but I can’t see it.
One of my windows was recently levered open from the outside, which snapped the 3 plates on the sill. The embedded lock in the handle seems of no value to protect against this activity. Or am I being dumb?