While minefields were common, the number of 'dummy minefields' was even greater, but even these were salted with real ones. It is indeed potentially accurate that fewer casualties might actually be taken by crossing the minefield, real or not, than would be received in the killing ground that they were designed to divert you into by avoiding them. Mines are as much a psychological weapon as a real one.
I don't know about urban fighting in WWII, but the Israelis used individual tanks (and even M109s) to back infantry platoons going building to building in Lebanon in '82... but they were part of a whole platoon attached to an infantry company and on the company net. Their platoon mates would be on parallel courses on the next streets, so not exactly isolated either. Having said that they also used M163 VADS as rooftop sniper suppression vehicles... so not perhaps the exemplar of conventional combined arms doctrine when all's said and done.