Millions of users still use old Android phones from 2018 with only 16GB of internal storage, and half of that is taken by the OS. For those users, storing ten 300MB movies (3GB) makes sense. Storing two 1.5GB movies does not.
These services are 100% legal and offer better quality than any 300MB rip:
The 300MB movie website is a relic of the broadband-starved 2010s. In the 2020s, it is a security minefield.