In my experience, people use it for street cred basically. Whether somewhat disingenuously to 'validate' (sic) poor content by mere association with the 'brand'

In my experience, people use it for street cred basically. Whether somewhat disingenuously to 'validate' (sic) poor content by mere association with the 'brand' name (cue Forbes, LinkedIn...), or more genuinely when 'legitimate' authors seek to give exposure to their sharing via the 'brand' platform (e.g. "Our <N> years of exp with tech <X> at shop <B>" by lead figure <I>). Which is a completely different approach than building one's own business. These platforms can still help drive traffic to a decent website though.