Unfortunately my answer is late but you can find a video about the Burley Baby Snuggler and riding a bike from 6 months is not recommended until 12 months.

It's like this. The Snuggler is a little more supportive, but it is far from a shell or hammock. The child has to sit.
There are shells from 3rd manufacturers, e.g. Weber.

The main difference between a hammock and a Baby Snuggler is that the Burley creates more of a "bucket seat". The support of the neck area is less pronounced in the Snuggler than in other hammocks.