I've used F15 landing in very nasty/turbulent landing scenarios (usually involving significant wind additives) as it lends itself to greater FLAP OVERSPEED margins during those gusts that are encountered during approach. F40 would certainly be out of the question because of the tighter margins associated with wind additives and lower overspeed constraints...lastly, do you really want your flaps retracting as you bust through the limits for blowup F30 or F40 with the gust factor?
Very good to practice F15 since that attitude is slightly different and will be used with an engine failure.