It's important to realise that most non-English people who want to learn English actually speak and spell in American, instead of in English. With that in mind, we realise that we can ignore their mispronunciations and misspellings, but then it bleeds into English. Years ago, I saw a bit of a programme about something and an American was happy with - what he said, not my words - "contaminating" elsewhere with American things, americanisms, americanisation. It's a metaphor for Spiritual Advancement - hang-out with undesirables, and you'll reduce to rubbish. (One user presumed or suggested ages ago that the reason why the Gods and Goddesses couldn't remain on Earth for these last several thousand years was because our vibrationary existence is too low for Them.)
Even then, on the very rare occasion when a non-English person wants to speak and spell in English correctly, presuming that they mean received English, then that also poses a problem - in the phrase "for example", "correct" English would be "for exarmple", but there isn't an R in "example". No matter how much "correct" or correct English one speaks, spells, writes and types, ignorance, arrogance, carelessness, etc., prevail, along with local differences, and "Does it matter?!" is mostly the question that is often asked rhetorically. Yes, it matters. Since "Satan" means "enemy, adversary", not "Truth Eternal".* That is why it matters, but then again "Meh", instead is the attitude and response, mispronunciations, misspellings, attempts at poetic licence instead of creating, using and perverting their own language, and learning actual English, and all; while actual English have actual poetic licence. Plus there's no such thing as "British English" and "American English"; English of is England; there isn't a British England and an AmericEngland. If there were, then "American English" might exist. Australian English. Canadian English... with colonialism, etc. (and for example the Philippines shouldn't be named the Philippines after the christian colonisation of the area by Spain).
Regardless of all of that, English is a bastardised language, anyway, but still - it's important to try to hold onto what we can, where we can, when we can, especially with melting pots and mixtures, to try and have what's our own, in our own, of our own, with our own. It would be great if a Zimbabwean went to Japan and spoke "Japanese" instead of Japanese, and promoted their own incorrect attempts of Japanese, wouldn't it? No?! SMH.
In short - it supposedly doesn't matter. No-one cares, and there's more than too much corruption within English, despite attempting to be English, remaining English, holding on to what little of English values, customs, identity, etc. remains that we can. Within English, the difference between how the toffs speak and how the commoners speak is significant. It apparently does matter. That seems to extend Earth-wide.
*sarcasm