More often than not, when we are searching for jobs that we want to apply for, there is more than one job that captures our attention and motivates us to want to put forward our application.
A challenge that many people face when looking for work is finding the energy and patience to tailor an application letter for each and every job. So, many forego the task of personalising their cover letter and just write up a standard, generic type letter and send it out to all the different kind of jobs they submit their resume for.
The positive side of this (Now I am scraping to find something positive from doing this) is that you can apply for more jobs more quickly in less span of time. The downside of sending out a generic cover letter is that the document may not capture the essence of what the employer is asking for. Nor will it demonstrate to the employer that you as the candidate would particularly like to work for their company/organisation and what you can bring to the role specifically for what they are asking for.