It's the cardinal rule for farmers,
"WHERE GREASE IS, MOISTURE AND CRUD CAN'T BE."
By keeping the HUB and the SPINDLE full around the short axle shaft (Stub shaft) in the front,
you NEVER have to worry about splashing a warm hub off in cold water again,
And the air spaces contracting and 'Sucking' in water.
Since there are no 'Air' spaces, they are full of grease, there is no way for water/crud to get in,
No way for it to migrate to the bearings if some does manage to force it's way in,
And you can flush your wheel bearings from the hub grease zerk from the center out without handling the bearings.
With the spindle full of grease, that little dinky spindle seal that is EASILY overpowered,
Is now reinforced by a 6" column of grease the moisture can't penetrate.
In stock trim, if the moisture gets past the spindle seal, and it's TINY and gets PACKED with mud!
The water/crud has direct access to the lockout and wheel bearings!
With the grease column in there, the water has NO CHANCE of getting to the wheel bearings or lockouts from that particular problem prone route...