The back end of a website is a lot like the creepy basement at your grandma’s house that scared the daylights out of you as a kid. Both serve a necessary purpose, but neither are necessarily easy or pleasant to interact with. Personally, I would pick SQL queries over baseball-sized spiders any day, but i admit that they can look like some of the most obtuse computer jargon out there when they get complex.
Nevertheless, SQL databases can present real advantages over simpler data structures like spreadsheets. A lot of the trade-off has to do with scale. A card catalog attempting to gather information about thousands of sources in a huge collection would be extremely unwieldy in even a well-organized spreadsheet. Excel is a powerful tool, but it has its limitations. Relational databases, accessed via SQL, can distill massive amounts of information down to a manageable format. Imagine searching for all the works of a certain author. Perhaps you don’t care about publisher information, simply don’t retrieve it.
In fact, a relational database can take advantage of the benefits of a spreadsheet as well. SQL queries can retrieve data that is then parsed into a manageable spreadsheet form. SQL also allows for a modular query structure: on the front end it might be as simple as checking boxes to choose which columns appear in your table.
Learning SQL and, more importantly, the art of constructing relational databases can be incredibly useful to a Digital Humanist. The goal of most DH projects is to present information in new, intriguing ways. Thus, it wouldn’t be surprising to find that an efficient system for storing your data isn’t available. At that point, it would be up to you to create your own structure.