Exactly.
If you hang the HN nipple waterer it's not stable and it's hard for the chickens to depress the nipples in order to obtain the water.
Agree. I just put ours on a couple of logs. Works great. A 5 gallon bucket filled with sand or feed/scratch (for weight) could also be used as a base.
I'm using a bird bath deicer in each bucket for winter. Low wattage, and only turns on under 40F, so economical to operate. I only had to knock a wee bit of ice off the outside of the HNs on a particularly cold morning, about -12F.
An additional note about HNs and winter - when it gets cold, the cold bucket plastic contracts, and you may get drips where the nipples screw in (even with the nipples with the silicone washers, which I have). Tighten them, and the cold brittle bucket plastic may crack, which will give you a genuine leak

. On below freezing days, you get kind of a cool ice sculpture, but on above freezing days, it's just a leak and gets your run wet.
Fixable, though, without replacing and drilling a new bucket. The cracks are usually very small, and a small square of duct tape inside and out on the crack has done the trick to stop the leaks I've had. Just remove the nipple, dry the area well, place a small piece of duct tape over the crack on the inside of the bucket and and another small piece on the outside of the bucket, and screw the nipple back in. I've repaired 5 small cracks this way with 100% success, and it was soooo easy to do! I even had some white duct tape, so the repairs are not seen at all.
Just another bit of info - I have 2, two gallon buckets for 16 birds and rinse/refill about once every 6-7 days when they're cooped up because of too much snow. Love them. Easy to manage, they're clean and easy to clean, and not too heavy to haul.