+1 to the mention of dyslexia etc.

Also it is way more than 1 second saved, if you are typing on a phone keyboard Why do you think nearly everyone who texts uses shorthand?

And then there's the Twitter effect. Just about every tweet is written in that style. Like it or not, the shorthand style has become acceptable, even normal, in some circles.

I find it fascinating that the OP thinks writing what most of us here regard as normal, informal English is "formal*.

I guess what we write would be regarded as sloppy to people 100 years ago.

I must agree, however, that the shorthand style is harder to read. Easier to write; harder to read. In a sense the author chooses to prioritise their own time over the time of many others. It could be considered selfish.

But perhaps the author's subculture is one where most people use that style, so that it's second nature for them to read it too.

There is a theory in language circles that "you" will be spelled "u" in 100 years time due to txtspk taking over.