I use 'em for my one cigar I smoke but I've never used 'em for pipe tobaccos -- I jar them at whatever their humidity is, and leave it at that (or leave them tinned). Cigars are more 'needy' of certain humidity levels -- pipe tobaccos are different. Some are intended to be dry, for example.
I agree that when compared to cigars, pipe tobacco is different, but not all tobacco is like Manil’s either.
Even as dry as Manil’s Tobacco is, there is still a level of humidity needed.
Go to Google as an example and type in;
‘what is the best humidity for pipe tobacco’
Now you should see the results on an article by SPC; ‘Proper Pipe Tobacco Humidification’.
Find the right moisture levels for the different pipe tobaccos you smoke by following these tips.
www.smokingpipes.com
Humidity at various levels does exist in Pipe Tobacco, what the individual pipe smoker wants to do with this, is a personal choice.
All Tobaccos need a certain level of humidity, it’s just a normal function of life.
There are only a few places in the world like Iran, various deserts, and the Artic, to name but a few, where humidity is only a few percentages, as in 0.5% - 1.0%. Tobacco isn’t grown in these regions, Tobacco is grown with and needs humidity.
What the individual wants to do with their tobacco after it’s grown is up to them.
Humidity simply explained is moisture, and all things in life need moisture to one extent or another.
en.m.wikipedia.org