We are an all-volunteer non-profit organization that receives ~300 letters/week. Being a little old school I cannot imagine opening an envelope without an opener. It's faster and neater making our entire process more efficient. We have lots of student volunteers. Actually I find it rather comical teaching the younglings to use a letter opener! Today's youth just don't send envelopes in the snail-mail anymore! :)
I've used this to open letters and other envelopes. Prior to buying this I used a finger. My finger usually got all gummed up and occasionally cut. When this letter opener arrived in the mail I had to use my finger to open it's package which was the very last time. Ironic eh?[...] I am very satisfied.
I wouldn't recommend this object for other uses primarily not for home defense (found that out the hard way). Breaks very easily when used for direct straight on contact...but works quite well with unopened letters and those envelopes that are not sealed very tightly but still look a little wet around the adhesive.