That's exactly it, most locks (bike or otherwise) are to reduce thefts of opportunity, or to otherwise discourage things. Bike chains and locks and the like can be clipped within seconds with the right tool (you can even get battery-operated hydraulic clippers these days, see e.g. [0]).
But if it's noisy or visible, it's discouraging.
Anyway, instead of paying a premium for a bizarre frame contraption, buy a cheaper bike with enough lock to discourage a quick snatch. It won't be worth the effort to steal on the one hand, and it'll be cheap to replace on the other.
If you get an expensive bike instead, get theft insurance and make sure there will be visible evidence of theft if it gets stolen (e.g. clipped chains or whatever).