There was another thread recently that posed a similar question about whether teams used CAD or whether CAD was essential.
The answer is: you can be a successful team and not use CAD. It is not essential. However, you can also build robots using just hand tools. Power tools are not essential. But of course they are extremely helpful and time saving.
(Hey, we made our robot with only a drill press and miter saw and hand tools. But, we also did use a lot of CAD
)