For me, that wouldn't be a benefit. The coolant in the radiator heats up faster than the engine oil in the sump, so the radiator's oil-to-water heat exchanger in the end tank serves to warm the oil up faster - a benefit in colder weather.
I wouldn't have thought this to be the case, but it is. I had a BMW with both oil temperature and coolant temperature gauges. The coolant would be up to temperature within a few miles in the winter, but the oil wouldn't heat up fully until I'd been driving for 20-30 miles.
