It is one of the best malware removers. Not surprised that it has attracted so many comments.
What you say is quite true, but Malwarebytes Pro does provide additional protection, as a companion to your Antivirus. Website blocking hasn't really helped me so far, although I must admit I really haven't visited any bad sites, so can't blame MBAM.
Scheduled scanning/updates is not necessary either. I prefer manual scanning and updates, although I do use MBAM Pro in realtime alongside Kaspersky. No slowdowns whatsoever.