Boveda sent me a free sample kit of their humidity packs along with a couple c-vaults. I tested 7 grams in one c-vault with no humidity pack and burped it daily. The second c-vault had a small 62% pack and also was burped each day.
The results 16 days later:
with pack-better smell, stickier and less powdery, slightly smoother smoke, high about the same.
without was far drier and less sticky, a little harsher to smoke( burned faster so more smoke per draw could account for this)
I did not tell my wife which was which and asked her to let me know her opinion.
Conclusion. They can preserve the weed better over a long period with humidity packs.
Another point is I have 9 month old pot in a quart sealer with no humidity pack ever but checked every once in a while for RH to insure close to 62% that is in excellent condition and a pleasure to grind, roll and smoke.