Maybe not a so much financial consideration as now but a financial purpose anyway. The sword can be a great copy but still a copy, and even in those past times swords were sold, and sold more expensive if greatly signed.The will to sign the nakago with someone else famous name has purely for goal to lead somebody astray, it is just a greedy goal.Furthermore, a lot of false signatures were added on th enakago sometime 100 or 200 years after the sword has been forged, in that case if it not a greedy purpose I do not know what else it is?
To conclude, as far I am concerned, a removed gimei sword is more respectable than a non-removed gimei one, even if a true mei one(or mumei) is the best of the tree!
I do beg your pardon for my so poor english.