Honestly, I’d never use it or others like it, but I and most guys here aren’t their target demographic. Most guys on MFA like fashion and consider it one of their hobbies. We enjoy looking at new collections, finding stuff we like, and finding great sales.
These websites are targeted towards guys who don’t care or know that much about fashion, but still want to look put together for work or potential suitors, and would rather spend more money than time on their clothes.
If you’re one of the latter instead of the former, I think they are probably pretty great set-ups. But you can definitely find all the stuff on those sites for less you if you’re patient.