Larger storage is good for videos (think Blu-rays, 4K videos are very big! Security camera feeds could also take up lots of space), and you might also want to host for multiple users (for family, friends, or a business)

But yes, _100_TB is a lot. 8-24TB (before memory became super expensive) was reasonable for most consumers, usually in a RAID configuration for redundancy. Multiple smaller drives are more reliable and modular than a single big one!