OTR trailers or Containers on trailer beds

Our community has some good expertise so, I’m asking a question.

From what I can tell, a standard seagoing shipping container can carry less cube but more net cargo weight than the equivalent OTR enclosed trailer.

My question is, out on the road, in a traffic incident, is the seagoing shipping container better for its cargo than an OTR trailer?

If the container is better, then why aren’t we using them, which allows more COFC traffic and the end for most TOFC traffic?

Most non-bulk cargos will fill the maximum volume of a 53' OTR trailer well before they begin to approach the weight limits of that same trailer, which means the trailer is often too small to be able to load to its maximum weight limit, so many shippers will want to use larger trailers rather than smaller containers.

This also implies that 20' ISO containers are only valuable for shipping goods where the weight limit of the container is met before the volume of the container is filled, which is why 40' and 45' containers are far more common than 20' containers.

BTW, this is also why you will often see that in a double stack train 2 20' dry containers do not have a 40'+ container on top of them -- the two 20' containers are heavy enough loaded that another container can not be stacked on top of them without exceeding the weight limits on the car (note that hazmat containers generally cannot be stacked upon and most tank containers are carrying hazmat in one form or another).