My parents decided to live in the UK after WW2; my father being attached to the Polish squadron in the RAF.
We only spoke Polish in the house & I got some funny looks from the kids in the street when I asked them if they wanted to play with my "straszporzarna" (fire engine!).

This spurred me on to learn (& love) the language as quickly as I could, & I have (but not without error) always tried to use it in the best possible way in terms of spelling, etc.

This was enhanced by a dedicated English teacher who would be quick to punish any mistakes!

So, do I think that it's important - well yes I do, but would never decry anybody if their language skills were not exactly perfect.

Would I expect reports, job applications to be grammatically correct - well, yes I would.

I am now getting quite adept at "text speak" to keep up with my children & friends, but only when I am texting, but I now find that this is now creeping in to everyday use - do I like this, no I don't.

Would that then mean, that without the incorrect placement of non desired wordage; corrective spelling and grammatically correct usage one could be considered to be ever so slightly verbose:so as to be pedantic even.