I turn my main beam off the second I see lights approaching, probably long before the auto feature would. Having spent a lot of time commuting on unlit B roads my pet hate is dazzling headlights and I give others all the courtesy I can. Your sensors don't know if your lights are dazzling oncoming driver, and leaving mains on longer does not sound good to me. This sounds like another ' auto ' feature for drivers who are not paying attention.
Having now had a car with this feature, I have to agree 100%.
I thought it was quite clever at the beginning, but after a while it became apparent that there are many instances where the forward facing camera cannot see oncoming headlights clearly, but the oncoming driver would have a direct line of sight to your full beam. I mentioned the issue with lorries and dual carriageways earlier, but there are other examples, even gentle bends and a low hedge or bank can leave you blinding an oncoming driver for a considerable time. Not only that, the HID lights fitted are extremely bright on full beam, it's like broad daylight, and carry for some considerable distance.
Even when a car rounds a bend in clear view, there is a short period when the driver is dazzled before both headlights are pointing towards you and the system recognises it as an oncoming car, and motorbikes are not always seen. I would have dipped much earlier in most cases than the car does.
It can also be fooled by tail lights too. With cars, it's generally very good at spotting them at distance, but it also insists on dipped lights whenever I'm driving towards directly at of the local power stations, which have red navigation lights up the chimneys. You see multiple pairs of red lights in the air on the 600ft stacks, but the car thinks it's another vehicle, even a mile or two away.
I mostly switch it off now, but the car turns it back on if you stop and restart the car. Maybe some systems are better than others, but if I could turn mine off permanently, I would. The other bits such as side lighting, auto lights and adaptive beam work well, but I don't like this main beam assist.