Working unofficially and unpaid after internship got cancelled, should one give full commitment if not intending to continue as a researcher?
Should you exchange your time for very minimal supervision (and no pay)? 

That depends on whether you perceive the value of very minimal supervision to outweigh the value of your time. 

You should consider whether alternative uses of your time (e.g., paid work, vacation, personal study, ...) are more valuable.