WCASET always claims that they are authentic. However, it's better not to fall for that. In Academia, to be honest, there's no 'extra benefit' you'll receive if your published with WCASET.
Moreover their Scopus indexed journals are not always Scopus indexed.
Having said that, they might have increase the quality over time, but the first intention is to make money. Better stick with the conference, journals belongs to your Research community.