Since Musing.io is a Q n A platform, I'm gonna break down my opinions into two parts.
For Questions: I strongly think that questions should be direct, clear, have a good sentence structuring and free of typos as much as possible. I have been a witness to many answers wherein they totally misunderstood the whole question due to a simple typo in it.
A good example for this would be if someone ask "How to get Steam?" - I'm a gamer and my first understanding would be Steam as in the digital video platform and not Steem the blockchain. This makes my answer totally off. As much as possible, people should double check first their question to avoid any future misunderstandings.
For Answers: I for one think that as long as the whole answer is understandable, then it is okay. The whole point of answers is to help and give an opinion, thought and information about something. So as long as that idea is delivered correctly to the one asking the question, then that's all that matters.
I agree with @jlordc, there should be leeway given for grammar mistakes in answers, but questions should always be clear and concise. Given the fact that questions take far less time to write, it shouldn't be too much to ask that question writers double check thier spelling and grammar and even research thier question to make sure that it is clear and free of misunderstanding.
I think doing this will improve the over all quality for everyone on musing.io and we will all benefit.