Many decades ago my father got grease in the 35-50# pails, and we would fill grease guns from them.
Some times we had a pump to load the grease guns with, much of the time you cleaned the grease gun unscrewed the end and used the rod to pull the grease using suction into the grease gun.
what a filthy dirty gritty grimy mess that always ended up being.
Then especially when it was cold out the grease gun would only be 1/2 filled and air pockets in the balance, having to loosen the end and try and purge the grease out,
way to many years of that crap.
Much working equipment gets greased every day, and some fittings may even be gotten a few times a day if experience has shown the need to do so.
The farm gets tubes of grease by the case and sometimes multiple cases. The grease guns work better, the grease does not get contaminated, air pockets and purging are mostly a thing of the past. It is quick, easy and clean to change out a tube. There will be times when we may go thru a couple of tubes per day. Many times air is not available where we are greasing and prepping equipment for the day. As far as the foot operated ones to many fittings are positioned were having to get a foot onto that pedal would be a contortionist joy.
So you boys go with the big buckets and pails, I'm for the tubes even when I'm using my pneumatic grease gun.
I may get a battery gun sometime, I keep looking but that's a lot of money to save very little work or time.
Interesting. I always thought bulk suction fill would be a mess, with potential grease contamination, but port filling? Besides maybe taking a bit of time (depending on your volume per stroke on your bulk pump), the only challenge I would see there is stopping in time, before you overwhelm the piston seal. And to avoid this, you could just stop a bit short and underfill. Probably good savings too, even with the purchase of a pneumatic pail pump to make refilling easier.