Search Engine Marketing or SEM is a marketing method where rankings are bid on, such as AdWords, Sponsored Social or PPC.
Search Engine Markerting is advantegous for many reasons. It enables marketers to target their audiences in order to get the most out of their impressions & improve conversions.
Some users prefer SEM ads as they find them more trustworthy, and certain topics/niches can benefit greatly by that added level of trust & targeting.
Additionally, smaller companies that are starting out can use this marketing style to ensure that their content is getting SERP impressions above the page’s fold, which may be difficult if they are competing against larger or longer established competitors.