The validity of a Journal conference is usually higher, since high quality journals use a blind peer review process. Conference papers can be just abstracts, working papers, essays, posters, presentations, etc.; whereas journal papers must (if the journal is indexed in WoS or Scopus) meet strict standars.
However, if there's a high profile conference (i.e the best or second best anual conference of a particular field), which usually has some associated journals with some reknown, a conference paper published there would have "more weight" than publishing it on a non indexed journal.
The issue with conference papers is that many conferences accept all the papers submitted to be able to attract presenters as registered participants to break even on cost. I advise my colleagues to only submit papers that have been rejected by archival journals to conferences if they want to strengthen their academic CV.
The peer review process with journal articles make the article height quality but the conference article can be just abstracts and the review process for conference papers is typical with general comments.