A microsite, as its name indicates it, is a small website, usually with a simple design aimed at promoting a product, service or in some cases to promote the company as such.
The main advantage of a microsite is the speed with which they can be developed since they do not demand as many technical specifications or a large amount of content.
A microsite is a site with the aim of promoting something.
Promote a product or service: Simplicity and size of microsites make them perfect to promote a product or service that a certain amount of time will be on the market.
Publicize the company: If your company is starting, a microsite is perfect for making it known because if the little content is optimized with keywords, the microsite can have a good positioning in SEO.