The funny thing is that this is similar to jounce/ Grand Prix/ fender/ radiator bars. Each one kind of does multiple jobs but they don't make huge differences unless combined. I'm genuinely curious just how much difference could be made by adding the jute and nothing else.
Possible key point for a T-Top: the CLD & CCF both adhere directly to the floor like super sticky tape, likely to not want to come off easily later. The foam is a gamble- it may not stick well, it might tear into pieces, it might roll up like lint. If you need to remove a CLD like "the Mat" then just cut the floor out or putty knives, a wire wheel, picks, and a heat will be your arsenal for a while. The jute can be pulled at any time if not glued to the floor. And even then you can remove it fairly easily. If future rust propagation or remediation is a concern then these attributes may factor into the decision.
Possible key point for a T-Top: the CLD & CCF both adhere directly to the floor like super sticky tape, likely to not want to come off easily later. The foam is a gamble- it may not stick well, it might tear into pieces, it might roll up like lint. If you need to remove a CLD like "the Mat" then just cut the floor out or putty knives, a wire wheel, picks, and a heat will be your arsenal for a while. The jute can be pulled at any time if not glued to the floor. And even then you can remove it fairly easily. If future rust propagation or remediation is a concern then these attributes may factor into the decision.