I've had success with halftracks in two QB's. One was at night in the fog. I had dismounted infantry scale a strategic hill overlooking a small valley with the victory location. On the right flank I had the HT's sweep around a small village with one mounted squad. With the HT's still unspotted in the rear I sent my infantry down in an assault on the valley. This drew the attention of the defenders there and, hopefully, distracted any enemies in the village as well. I sent the HTs and the now dismounted squad at the village from the rear and surprised an allied HT and an armoured car. Mopped them up with no losses. The infantry in the valley meanwhile was fighting for their lives against dug in riflemen and a gun of some kind. With the village secured I formed a loose line of the HT's and crept them towards the woods (to concentrate firepower and confuse with multiple targets). After the gun was overrun by a decimated squad I rolled the HT's forward as one and filled with woods with machinegun fire. That was the end of that. Lesson learned: If they can't see you they can't shoot you - HT's and presumably scout cars are lethal on night missions if used boldly and offered some infantry support.
The other example is probably obvious but when defending a town, again as German, I wanted to keep my men in cover and hidden but to slow the advance of the Brits. Mortars helped (placed behind a building with a very effective combat leader) but the HT's could speed down alleys, pop out where needed, fire and disrupt an attack before retreating unseen. I lost one to tank fire and another to an arty barrage but two lived very active lives and survived the engagement.