Pairs of cone wrenches?

Sorry if this is a really dumb question, but why are cone wrenches sold as pairs in kits? The Pedros apprentice bench kit comes with pairs of 13mm, 14mm, 15mm and 16mm cone wrenches.

I've yet to service my own hub, but in videos I've seen, one is used to hold the cone, and a larger one (or a ring spanner) is used for the lock nut. When would you really need say two 15mm wrenches at the same time? Is it possible for the lock nut to be the same size as the cone?

Again, apologies if I'm just being dense here.