Depends... :)
You could keep them to show off your growth and to motivate other artists by allowing them to see said growth when they check out your profile.
Other than that... It might serve as proof in the future that you are "probably" using AI to create your submissions.
Depending on how poor 'you' think they look, you could set them up in a way that the rating doesn't show and shove them all into one single Art Portal submission. That way they wouldn't spam your profile or lower your chances of getting/staying scouted.
In the end, it's up to you, though. It's 'your' work - and if you are not comfortable with sharing it publicly, then don't.
walllrus
Nah I think you should keep them. You might regret deleting them in the future