Hi,

Good question. If you apply for a free account at steemit.com you need to provide an email and your phone number and it can take a week or two until your account is created. With Steem.Ninja you can create your own account within minutes. We offer this service to allow people to easily get started with Steem. If you have more questions I would like to invite you to our Discord server: https://discord.me/steemninja

Regards

The Ninja