A checker is a second reader, not an editor

Automated checking is very good at one thing: catching the mistakes your eye slides over because you already know what the sentence is supposed to say. It is much weaker at judgement. Style suggestions in particular are worth reading and often worth ignoring — a checker cannot tell that the repetition was deliberate or that the sentence fragment was the point.

Treat every suggestion as a question rather than an instruction. The ones about spelling and agreement are nearly always right. The ones about wordiness are a matter of taste.

What still gets through

The hardest errors for any checker are real words in the wrong place. Their for there, its for it’s, manger for manager, form for from. Modern checkers catch many of these from context, but confidence drops fast in technical writing and with proper nouns.

The second blind spot is your own domain vocabulary. Product names, internal jargon and industry abbreviations get flagged as misspellings, and after the tenth false positive it is tempting to stop reading the list. Skim rather than dismiss.

Why spelling still matters commercially

Search engines do not directly penalise typos, but readers do. Visible errors in a headline or a product description read as carelessness, and carelessness in copy suggests carelessness elsewhere — which is a fair thing for a customer to conclude. On pages where someone is deciding whether to trust you with money, proofreading is cheap insurance.