system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is microSD cards affordable and have high capacity of upto 1 TB and very small compared to SSD and HDD?
gpt
Micro SD is really good at being small, but not great at being the things a typical SSD or HDD is good at.  Most notably, the microSD isn't good at doing lots of things simultaneously, or in queue (quasi-simultaneously).  If you think of the uses of micro SD it's usually just _storage_ on devices that use that storage for one thing at a time.  For a SSD you are running lots of applications at the same time, or maybe you're a server handling thousands of nearly simultaneous web requests.  The capacity to read and write rapidly and efficiently and in parallel and buffer large amounts of data is not something a microSD card is good at.