This is so common. Lot of time, they use CSS to change the design of the module, which is how it should be. But when they revert the look of the module, instead of deleting CSS, they add new rules to overwrite existing CSS. Which leads to specificity fight and !important.
At my previous job, site was rendering on server. It was old, and we wanted to redesign it. I wanted to keep rendering on the server. CTO and VP wanted to build Angular site because everyone is moving to Angular and its easy to find Angular developers. Company's 30+% of new visitors comes through SEO.