In this short article we would like to get rid of the general misconception that bubble envelopes are a good protection when shipping trading cards. In fact, they are not. In most cases they are even worse than normal envelopes.
Trading cards are not fragile objects, but soft objects. Thus the danger does not come from shocks but from being bent. Thus a proper packaging needs to be strong and rigid, for example a toploader or cardboard / postcards. Bubble envelopes do not offer any rigidity as they are made of soft plastic.
No it is not. A trading card in a toploader is very well protected against „normal bends“. However when putting the toploader inside a bubble envelope 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 usually means heavy damage to the content.
It is not forbidden, there are ways to correctly use bubble envelopes (but they are not easy and even if you do, the offered protection is not better than the one from a normal envelope). So Cardmarket will always suggest to go by 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".