This has zero to do with Adtech for 99.99% of uses, either. Web devs like to write TypeScript and React because that's a very pleasant tech stack for writing web apps, and it's not worth the effort for them to support a deliberately hamstrung browser for < 0.1% of users (according to a recent Google report).
See also: feel free to disable PNG rendering, but I'm not going to lift a finger to convert everything to GIFs.