Well yes and no. They aren't going to provide anything the original rubber gasket hammer-on lids give you if you're talking about long-term storage. I'm not looking to use these for super-long-term storage however. Right now we're keeping lots of stuff in dry storage in the garage since we only have so much closet space.
The stuff in the garage I don't need to keep in ammo cans (like brass to reload) goes into 5-gallon buckets. And I use those enough that the hammer-on lids became a hindrance. My 5-gallon buckets brass (one of .45 ACP and one of .40) is almost full, so it is nice to have the ability to screw on/off the lid when I get another handful from range visits. Way too much to keep in ammo cans