The dog engagement is designed to be banged into gear and ideally flat shifted which is impossible on a road car. If you pussy foot around trying to select gear without crunching it then you are much more likely to do just that and cause damage to the gear.
Also the gearing is a higher ratio than standard gearset so ideally you need the 5th even if it's just to rest your ears on a motorway from the constant whine of the straight cut gearing.
So it depends what car is mainly used for but tbh I think a straight cut synchro is always going to be the best option unless it's purely used as a full on track car
That's my opinion anyway