There are times when local colloquialisms and slang can make a piece of copy better - but a corporate website meant for a highly professional audience is not one of them.
In the professional world, basic grammatical errors can demonstrate unprofessionalism and put off potential customers and clients. Poor grammar and presentation is not only confusing and misleading to readers, but can also give a poor impression that may be impossible to reverse.
As such, copywriters can and will write clear, concise, error-free copy when necessary that is not only impressive but also satisfies (current) search engine web page ranking algorithms.
However, a copywriter’s grasp of the nuances of grammar means that they can bend the rules if it can achieve the intended effect of making the writing more exciting and entertaining without losing the real meaning. After all, grammar is constantly evolving to convey new ideas or old ones better - and its use ultimately depends on the context.