Nope. Since the box normally runs with no pre-load on the peg, and the spring adds pre-load, then the spring has to add steering effort (high school physics, friction is proportional to normal force). It may not add very much (depending on how stiff the spring is and how far it's compressed), but it cannot ever make steering easier.
In theory, it can remove on-center play with a significantly worn worm. That's probably worthwhile, if your worm is worn enough to make on-center play a problem. But I've driven an old, worn-out box for so long that a bit of play at center just seems normal to me, and it's never been a problem otherwise as none of my TRs have tended to wander as long as the road surface was reasonable. (Once drove over 20 miles on the Beeline highway without touching the steering wheel.)
And since new worms are now available, I would think that would be a better alternative.
I probably couldn't parallel park with just my little finger (never tried that), but I could with one hand, even with wide, sticky, steel radials.
Of course, as Geo says, YMMV. NFI as well.