What "climatise now" does
The engine starts, the climate control runs at the settings you left the car with, and where the car has them, the seat heating and the heated steering wheel come on too. After 15 minutes at the latest, everything switches itself off.
You start it with three presses of the lock button on the key, or from your phone. The car stays locked the whole time.
What no parking heater can do: cool
A classic parking heater burns fuel to make heat. In summer it does nothing for you. Preconditioning through the engine is your car’s ordinary climate control, so it heats in winter and cools in summer.
A retrofit with nothing to install
Retrofitting a parking heater means installation, plumbing, a workshop, and depending on the car a four figure bill. Enabling Remote Start means activating the function your car was already built for. No part is fitted and no wire is run; the activation is coded onto your car while you stand next to it.
BMW’s name for the function is Remote Engine Start, option 1CR. If "climatise now" is missing in your BMW app, it is not enabled on your car, and that is exactly what Casto Flasher is for.
The honest difference: the engine runs
With Remote Start the engine runs while the cabin is conditioned, and it burns fuel doing it. Do not use it in a closed garage, and mind the rules on running a stationary engine where you park; Austria and Germany both have them.
After 15 minutes it stops, a limit the manufacturer builds in. For glass and cabin that is usually plenty. If you need hours of engine-off heating, you really do need a parking heater, and we would rather say so here than after you have paid.
Whether your BMW can do it, the app tells you for free
About 5 minutes at the car, nothing is changed, and you only pay once your own car has said yes.