There are many examples of the ST1300 going 200K, 300K, and 400K miles with simple regular maintenance and 10W-40 oil. There are examples of the NC700 going 100K and 200K miles with the recommended oil. I'm not worried about it.If one lives in a hot climate it certainly can not hurt to go up one grade and only makes sense to do so.
Engine wont blow up if you dont do it but I think just common sense to go up a grade.
Engine coolant temperature does not perfectly correlate with oil temperature, the coolant is temperature controlled not the oil and in a hot climate it will run hotter. In fact in a hot climate even the engine and coolant will run hotter but the oil more so.
None of these 10w oils even make sense if you dont ride in temps below 50 degrees and many of us in the South do not.
The chart above says good for -10 F well ... not many riders who ride in -10F .... Ill be happy with +40 F ) and I dont ride until 60+ F and for the a solid 3 months will be daytime highs 90 to 100+ but then again, my bike calls for 50, my previous Yami Vstar 1300 called for 10/40 and I used 20/50 summertime.
If I had an air cooled engine, I would be more concerned.