Not sure why this is downvoted. There are plenty of degrees that might be useless for making an employer more money, but provide important work for society.

You can study whatever you want, wherever you want, without criticism or question if you are willing to pay your own way.

Very well, but what is your objection to zoology? Normally, people pick an arts subject when arguing about poor-value degrees.

Zoology is a biology course, so there's a general scientific background (research, hypotheses, statistics, modelling etc), and zoology in particular is necessary for understanding the spread of animal pests (e.g. insects eating pests), invasive species, human and animal disease (bird flu?), understanding/recording what is in a particular place (perhaps before construction work, or to guide the planning of that).

The report on the lowest- and highest-paying majors ranks zoology fairly highly -- above chemistry and physics: https://cew.georgetown.edu/cew-reports/valueofcollegemajors/