This site will eat your SSD. It is intended as a proof of concept to warn people of what a site could maliciously and silently do in the background.
This uses a technology called IndexedDB that some sites and PWAs (Porgressive Web Apps) use as a way to store big data long-term. In order to eat your SSD, we wear it by writing on it as much as possible in big chunks of 1Mb. All write operations anturally wear down SSDs, this will be significantly worse than a normal regular usage. Left running a few hours on a modern NVME pcie gen 5 drive, this will kill it.
No. If you have a classical hard drive, this will not wear it down nearly as much. Hard drives usually die from physical shock, or mechanical wear from the years of use. They are not susceptible to heavy constant writes as much as SSDs, therefore your HDD will live. On a side note, you should really upgrade to an SSD if you still have an HDD as your system drive, you will enjoy a 10x speedup in your daily activities for 20 bucks.