In this short article, we wish to address a common misconception that bubble envelopes provide proper protection for shipping cards. This is absolutely not the case, and, in many cases, they are even worse than normal envelopes.
Trading cards are not fragile objects, but soft objects. As a result, the danger doesn't come from "shocks," but rather from bends. To combat this, proper packaging needs to be strong and rigid. Cardboard, postcards, or toploaders are some good examples of rigid protection. Bubble envelopes, on the other hand, do not offer any rigidity as they are made of soft plastic.
No it is not. A trading card in a toploader is well protected against "normal bends." When putting the toploader inside a bubble envelope, though, you actually take away a part of this protection! As the bubble envelope is bigger than the toploader, you will have a "soft part" around the toploader. This soft part is much more likely to be "caught" between other parcels or within the letter transporation systems the postal services use. And this can mean heavy damage to the content.
It is not forbidden and there are ways to safely use them, but the protection they offer is not better than a properly fitted normal envelope. So Cardmarket will always suggest users use the following packaging guidelines:
You do not want to have your buyer to receive this … and then claim, "but I used a toploader inside a bubble envelope."