Anyways is a colloquial variant of the adverb anyway. It has a casual tone and may be considered out of place in formal or serious writing. In such contexts, anyway is safer.
Although considered informal, anyways is not wrong. In fact, there is much precedent in English for the adverbial -s suffix, which was common in Old and Middle English and survives today in words such as towards, once, always, and unawares. But while these words survive from a period of English in which the adverbial -s was common, anyways is a modern construction (though it is now several centuries old).
Anyways is sometimes useful for creating an informal or colloquial tone, which may be what these writers have in mind: