"I want to put together an online seminar for my employees using WorkTrip but I don't need them to register or provide hotel information. Can I get rid of the registration process?"
If you are putting together an online event like a seminar, it is more than likely that it will only be around an hour or two. Because of this, there really is no need for people to register.
When creating your event, leave the Require attendees to register toggle disabled.
This will remove the registration requirement for your event. It will also remove the hotel feature, so no hotel assignment will be required.
You can also put the link to your online event as the event website.