And the downside is if you drop it in the toilet or sink by accident, it no longer works.
My Aladdin token has a button, as well. I assume it also helps to save energy, they probably don't go dead after 2-3 years like the securid ones do.
My last SecureID dongle lasted 5 years. It auto-shut down when the token expired. (I got missed, somehow, when they were doing the 5 year replacement). Always-on. I left it on my ID badge (uses a lanyard, lives in a backpack when it's not around my neck).
You do want to keep the thing roughly room temperature. Long periods in extreme heat or cold will nudge the internal clock out of synch with the RSA servers.
It REALLY beats a 12 digit, changes every 30 day, password.