Since I have all of the above, I can share with you my experience. The sole place where I found it to matter is printing with PETG, ABS and PC. I have no experience with ASA.
One of the first differences I experienced was when I printed at bed temps above 80c. The leave this out of the fine print but if you do not let the plate cool at 100c, PEI will soften. How do I know this? Take a look at what the metal scraper did to a PC print I tried to peel off in haste.
Now that’s not to say that you can simply use the high temp or engineering plate without a coating. Once you print at 80c or above, you will find that you will need something like a glue to act as a release agent, not so much as a binder. What happens when you don’t? Well I have a picture of that damage too on a smooth PEI plate and a specular PEA plate.
Permanently stuck PC on a PEA+PEI plate
PETG scars on a smooth PEI plate where I failed to use any coating.
So in short, I can tell you that even though it says directly on the Bambu plate the following:
I have a difference of opinion.
Since most of my printing involves non-PLA I find that I leave my engineering plate in the printer for almost everything. But I will also note that I coat it with 3 light coats of hairspray to protect the surface. It generally will allow anywhere from 5-7 prints in the same location on the plate before I need to reapply.
Don’t make my mistake, PC at 100c ruined my original black PEI plate but to Bambu credit, they did make good on it and sent me a new gold PEI plate even though such damage is not covered under warranty. However, if you are going to try PC or PETG on a smooth PEI plate, use hairspray for a uniform coating that will act as a release agent. I would experiment with small parts located at the corners of the plate where you won’t be so upset if that part of the plate is ruined. Unlike me, who like a dumbass, went full speed without testing and ruined the center part of the plate.
FYI: Using multiple coats of hair spray thickly applied and allowed to dry will remediate any smooth plate to at least a smoothness. Here’s what a high temp surface looks like with 4 layers of Aquanet Hairspray(unscented) and was placed in my kitchen oven at 100C for 10 minutes between each coating. You can tell I overdid the spray on the last coating because it dripped. I don’t have a photo of a plate after I mastered the use of hairspray in lighter layers. But even with the drips, look how smooth the surface looks and I can share that this particular print was PETG and if you look at the bottom left print, I was able to achieve optical clarity. This was in part do to 0.08 layer height but also the smooth print bed made all the difference.
