I primarily think of it as an alternate orthography used for making searches easier, for implementing fonts, or any other situation where Klingon's use of capitalization and digraphs is inconvenient. I don't think of it as something anybody actually uses for writing Klingon. (Although I can imagine someone doing it as a way to mimic internet-style writing that's heavy on abbrevations.) Also, there are a few minor variants: some implementations use q and k for q and Q respectively, but some do the opposite. boQwI' uses z as a shorthand for the qaghwI', but I think most other places use just an apostrophe.

There are also a few puns that are based on it: tlhapragh and vI'Ir are the first two that come to mind. (The latter suggests that MO uses boQwI' with the xifan hol option.)