I guess it depends on your personal risk assessment. I rarely leave mine in a car, but when I do, I just stuff it under something... I really haven't personally come across any car safes that I thought would really stop someone and where also affordable... IMHO it is a feel good mood and mostly gives someone a false sense of security..
"Stuffing your gun under something" is probably the ultimate false sense of security.
I personally have come cross car safes that stop people for the length of time I needed, as I researched them and ultimately bought one.
I handed it to my 8 year old grandson and told him to try opening it using the combination, and after many tries it shut off.
I reset it, had him try again.
No luck.
No hammer or screwdrivers for he or any other child to use on it.
Perhaps we could have an experiment where we place your unloaded gun "under stuff" in your vehicle, I place mine in my gunsafe, we let three elementary kids play in the vehicle, and see which of us two breaks out in a sweat first?
By the same token, if someone wants to sit in my vehicle in broad daylight and try to open the gun safe while I'm buying a book of stamps, then so be it.
I used the door pocket of my truck these last several years, and I can say for a fact that I know it's safer in my gun safe that either cannot be opened or takes many minutes, than just reaching into my door and taking it.
Especially since my full frame S&W M&P isn't concealed by the door pocket.