Seeing as I always use numbers anyway, I never have an issue, but in the digital age, numbered cues are a bit easier than lettered cues in many applications.
For example, I have a piece of sound playback software which allows me to type in a cue name and press enter to skip cues, or just use enter to go. So I carry around a small USB number pad, and sit my playback machine (my laptop) up on a stand, and the number pad next to my sound desk. Typing 105 on a keypad is easier than typing CA for example.
If I am running the sound desk as well as the sound playback, I really don't have room for the laptop, except to sit it beside me on the drive racks - that puts me in a bad operating position.
As SM's, we really do need to be adaptable.