Recently I needed to make a call and the only number I had was a mnemonic one. I get why they are useful, you want something easier to remember than numbers and perhaps just memorable in general, but my phone doesn't happen to have the letters on the keys (BlackBerry curve). Then I'm looking around for a phone with real keys.
Turns out that there is a reasonably simple solution on the Blackberry, just hold down the ALT key and enter the letters, when you hit dial it converts them to numbers. Yes, it's apparently in the manual, but seriously, is that something I'd be reading? It's a phone!
So business people, what I'd wish for is that in addition to the memorable number put the actual number in parentheses after it.