Why did you find out the details of data storage AFTER you purchased Blink vs. BEFORE you purchased Blink?
btw, if you need to constantly be busy downloading video clips to your computer, that batteries will die somewhere between a few days, to a few months. Possibly a few hours. Camera may also overheat and fail.
Bottom line is you can not take a system like Blink, Arlo, Nest, Ring, Wyze, etc. and turn it into a traditional security system. These are home monitoring occasional use only systems. It’s why the price tag is so dang cheap.