Monofilament fishing line (or Mono for short) in itself can be made to showcase a number of attributes, some are designed to be more supple, which will enable it to lay much nicer on a reel's spool and be much easier to tie knots with. Others will be harder, and more abrasion resistant, which will be better when fishing around structure, such as off the rocks.

Mono generally has up to 10% stretch in it, which helps when cushioning head shakes, or leaping fish, but again, some brands make mono line with less stretch, which will thereby increase the sensitivity of it.
Mono fishing line is a fantastic choice when estuary bait fishing, shallow water float lining, or when trolling for game species such as Marlin and Tuna.