Gerd Shraner insisted that it did improve durability and stiffness, even with modern rims and modern swaged spokes. He also said:

"The wheel becomes a little harder, responds more
directly when riding upright and is faster when
accelerating - qualities highly appreciated by amateur
and professional athletes alike.
Tying and soldering also offers advantages for the
front wheel, increasing durability and allowing it
to be steered more directly when riding upright."

But Brandt's experiment disproves at least the strength part.