People who study something inherently interdisciplinary like Classics tend to develop excellent reading and writing skills, usually also good oral communication skills, an understanding and appreciation for various different cultures, usually quite a bit of historical knowledge, and usually a broad familiarity with the application of a variety of social sciences.
As a result, Classics is considered among the best majors for people interested in something like law school, as there is a very high degree of overlap in important skills and attributes. It is also the sort of major where a lot of people end up going into business, again because of all the overlap in desired skills and attributes.
Yes, it is a bit unfortunate to me a lot of kids I encounter these days seem to think college must be about acquiring specific technical knowledge in preparation for a specific job. It can be, but there are still many professions, and employers within those professions, who do not think college is really a good place to learn such specific knowledge. Maybe postgraduate degrees, maybe employer-specific training, and often most importantly, through actually working experience. But not so much college.
So what they do like to see in college students is people who really develop their fundamental skills and basic background understandings. And a wide variety of majors can be suitable for that, but it certainly includes core humanities majors like Classics.