A little bit of bullhockey there I think. They are summer tires, and so don't do well in the cold, but that's a lot colder than 50 degrees (nearer freezing). Secondly, I'd doubt they'd ever be worse than the OEM GY Eagles - which are also summer tires.
Having said that, I personally have the Conti DWS (U.High Perf. All-Seasons) since I drive year round. I'll give up the top level of grip for all-year useability.