Why USB flash drives are helpful
A regular quick access need in the digital age of information makes the USB Flash Drive almost a requirement even with cloud services being so commonly available. The portability of a USB Flash Drive makes it extremely convenient as you can carry anywhere from a few GBs to 2TB of storage on a keychain! Based on the Flash Memory tech that doesn't use moving parts but electronic circuits to store and retrieve information making it more durable and quick to perform its tasks. Although the more deletion and rewrites the drive bears the more it degrades over time.
A great way to move around files quickly or use as your workhorse for storage of project files you need to use while travelling if you have them on you and all you need is any computer to be able to work on them. Essentially needing just the USB Flash Drive to be able to work as computers have become commonplace devices. Aside from the basics of storage a device can house an application, run diagnostics to figure problems or launch an OS from a bootable USB. Some brands also develop versions that are password protected so each time it is inserted it shall require a code to be accessed.
The drawbacks along with all this convenience include the chances of it picking up malware, data leakage as it is a small device that is hard to track so it could be a security risk and a relatively fixed number or write/erase cycles before it eventually fails. These cycles are in the thousands so are ample for you get a decent amount of usage from a drive before it stops functioning at top efficiency. All this is, of course, also dependent on how the drive is used and maintained. If a USB Flash Drive is regularly scanned and when inserted isn't accessed from the auto-run feature but instead the explore-window in Windows it will probably be safer and last longer. Also, it is recommended to properly 'eject' a USB instead of just pulling it out once you are done with your work as this can cause file corruption.
Space and speed
Available with storage starting at a few MBs up to 2TB! The prices keep going up along with larger storage spaces. The transfer speeds also vary from USB 1.0 up till USB 4.0, getting faster speeds as the versions move up the number scale. Major producers of the USB Flash Drive include SanDisk, Seagate Technology, Sony, HP, Lexar, Kingston, Verbatim and Toshiba - the original creators of Flash Memory tech in the 1980s.