They aren't convenient when you have to spend 30 minutes swiping to keep your "relevance" up (a stat of your profile tracked by the app to push you to more people) and the only alternative is to pay money. And finding your soulmate is a needle in a hay stack when the seemingly majority of accounts you're swiping through are either OF thots advertising their socials or scammers.
You say that as if the only alternative is going on blind dates. God forbid you go out to social activities and get a feel for someone in a friendly setting before developing an interest.
I'm not arguing anecdotes, the apps are designed to make the average person fail so they pay up for what they perceive will be a better chance.
There was an online dating service I forgor the name of that had used a personality quiz when users signed up and had a pretty good success rate with matches. IIRC it was bought out by OKCupid and turned into the same slop as tinder/bumble/etc.