I would imagine that many of SZ's readers are using Fakebook style charts, rather than full score. The smaller size isn't much of a disadvantage there.

But bottom line is, do you really want to go out on a professional show, and have a huge laptop or MusicpadPro perched in front of you, so you can read off of full charts, or do you want to LEARN the songs at home, and go out and do them without the charts, or at most either read some trigger lyrics (short phrases to 'trigger' your memory into remembering the full line) from your arranger's display, if it can do lyrics..?

What looks best to your audience?

But if you are doing this at home, a laptop or computer display is just fine. And you aren't limiting yourself to tablet apps and limited capabilities.