The DHS website allows one to apply for an I-94 online before arriving to the actual border. The description on the page says that:
To complete your I-94 application you will also need to:
Appear at a port of entry within seven days of completing this online application. If you do not appear within seven days or are not issued an I-94 for any reason, there are no refunds.
At the port of entry, submit your biometrics (if required) and complete an interview.
Please bring the documents you entered into the application with you to the port of entry.
Be prepared to show evidence of your residence, employment and/or travel plans, if asked by the Customs and Border Protection (CBP) Officer.
... which sounds like exactly what you have to go through if arriving without a pre-application. Does it therefore make any sense to apply for the I-94 online in advance?