To work with software patents. There is a specialized type of consultant known as a “patent agent” who is licensed with the US Patent & Trademark Office, and who can help clients get their ideas patented or deal with other patent-related issues. There is an equivalent type of lawyer known as a “patent attorney”.
To qualify as a patent professional, you have to pass a difficult USPTO exam. To qualify for the exam, you need to demonstrate a certain level of technical proficiency. The easiest way to do this is to have an approved undergraduate degree. This can include a CS degree, but it has to be ABET. The rationale is probably to exclude less rigorous programs, such as the non-ABET CS or IT programs typically found at unselective for-profit schools.
ABET is generally important in technical fields where there is government licensing (particularly civil engineering), but is generally optional if licensing is not involved. In CS, there is generally no government licensing except for a small number of patent professionals, and so ABET is typically regarded as optional. There are alternative ways to qualify for the patent exam if your CS degree is non-ABET.