have been using without any ROM drive for past 4 years. other than watching DVD or Blu-ray, there isn't much use nowadays.
Software installers all come in digital download form.
reformat - can use USB thumbdrive to setup windows OS, do repairs, cloning, etc.
back-up - nowadays not much ppl burn DVD or Blu-ray.. most use USB harddisk or Cloud.
If needed, just buy external USB 3.0 DVD-Writer or Blu-ray writer drive.