Gaslighting is just one type of microaggression.
Microaggressions appear to be small slights, but substantially contribute to a hostile work environment. From the outside, they look innocuous enough; more like clumsy misunderstandings, but a persistent pattern of them can wield tremendous damage to teams.
A pattern of microaggressions directed at a team member results in impeded productivity, undermined confidence, and a sense of not belonging.
Workplace bullying and unfairness have been cited as the primary reason that women, PoC, and LGBT individuals leave the tech industry; people from these groups leave at such a high rate that the attrition costs a total of 16 billion dollars per year. It works against inclusion and diversity goals on teams.