The world is a dangerous place for photos. Sometimes it seems that almost everything in the world, from the air to the sun and virtually everything man-made, is bad for photos. Luckily, there are products and techniques that can and have been proven to do no damage to photos. These products and techniques are known as "archival".
Unfortunately, the term has taken a lot of damage, recently. Mostly from marketers. I've seen the term used to mean "absolutely, totally safe forever" and "shouldn't do any harm for 10-20 years". We must be careful to use the term properly. There is no "almost archival". It either is, or it ain't.
Just because a photo is stored in archival materials doesn't guarantee a long life for it. One of the worst culprets for photo degradation is the photo itself. Sloppy or cheap processing, "new, improved" printing materials, and sometimes simply the inherent ingredients themselves all conspire to rob us of our memories.
But, we must do what we can.
It should be noted that digital copies are not technically archival. Most optical storage is rated at about 15 years, and magnetic storage is less than that.