"Best glide speed" is the speed at which the airplane will achieve the greatest distance over the ground for altitude lost. for some airplanes, a comfortable power off approach speed will be faster. At least it will give you some reserve for an imprecise flare, which can happen under the stress of an actual engine failure. Crossing the numbers 10 -15 knots fast is generally manageable, particularly if it's planned. I was training this last week, with a good slip held right over the numbers (flapless plane). I won't criticize a pilot who makes a successful forced landing. Sure, we could all armchair it to have been better, and learn to be better ourselves, so let's do that too. For me, cross the numbers power off at "best glide speed" may be on the less comfortable side of safe, for a pilot who's not right up on the type. When your flares are judged and timed with excellence, consider flying best glide speed into the flare.
By the way, the flapless type I mentioned does have a remark in the flight manual about increasing speed above glide speed for a power off landing.