If you want people to use Steem they need to be able to buy it and even more important: To send it to their Steem wallet/account. At the moment I do not know any other possibility for newcomers to do so beside of openledger because of the reasons I showed above =)
Thats why it is even more important right now to have additional market places on board than before (imo)
There is also BlockTrades, but yes - you are correct :)