If it's an old matchbook, it's best to always ship in a rigid container to keep from crushing the matchheads and turning them to powder. I sometimes use a small pillbox to protect the matchbook and then ship in a bubble mailer. Or you can just use a rigid box and place the wrapped matchbook inside.

I get matches all the time in the mail. They are seldom marked "ground only". Safety matches are very hard to ignite without bringing the match into contact with the striker. Wrapping the books individually in foil is a "belt and suspenders" process. Even if very unlikely, if a match should ignite, the foil will keep oxygen out and the book will self extinguish. Individual wrapping also keeps matchheads away from the strikers on other matchbooks in the shipment.

There are pretty strict regulations regarding carrying matches onto an airline flight. Particularly if you are wearing shoes with thick soles.