Call me old school but I prefer songs sung in tune in the first place and NO autotuning, melodyning or anything else other than reverb and perhaps an occasional touch of double-tracking, though making it a duet with a suitably harmonious partner would be better IMO. Real instruments too (if only!) and no singing to prerecorded backing tracks!
Then, we'd know who can actually sing properly and who's there (and on recordings) just because they look good on TV. Rarely though, a slightly off-pitch song or part of it can sound quirkily interesting - usually by accident not design though!
You may want to listen to PiL's 'Metal Box' and see wnat's possible.
It's not how you sing, it's what you express.