Listening to John is like a broken record. There are lots of decent waterproofing products out there. Kerdi has been used worldwide for nearly a quarter century, most of the others are much newer - the Laticrete sheet product came out this past April...while I believe it is good, they have no track record with it. Kerdiboard, when used in a shower, has all edges and penetrations sealed...the surface is waterproof. The foam is an extruded version of the same chemical foam that millions of foam coffee cups are used every day are made of...they don't leak. Then, throw in the stiffening, thinset holding surface, and you've added additional water/vapor/thinset features to the material. If you use DitraSet, you'll notice on the spec sheet that it works as both a thinset and a medium bed mortar, and that they have a range of water you can add to it. Most thinset manufacturers magic mix is designed to only work with a very specific amount, Ditraset does work fine as long as you are within that range. Anyone that says to overwater the thinset does not understand the Kerdi/Ditra installation instructions. Use the max for embedding the fleece of the membranes, and you can use less, especially if you have a larger format tile where a medium bed mortar might be needed. Mapei also makes an uncoupling membrane mortar that works quite well.
If you read any of the spec sheets for any available thinset mortar, dryset or modified, it will list bond strengths to various types of tile, porcelain included. What some people just don't seem to be able to grasp is that there is a big difference between bonding to a solid surface like cbu, plywood, or a concrete slab and bonding to a membrane which acts somewhat like it's own microscopic cleavage plane. While you may find bond failures using an unmodified where a modified was specified, you really do not see failures when a dryset mortar is used, as specified, when used over a membrane designed for it unless there is some workmanship error (like poor coverage, letting the thinset skin over before setting the tile, improper substrate prep, or excessive deflection, etc.).
The industry guidelines as outlined by the TCNA (Tile Council of North America) give some specific warnings about a latex modified mortar used between a waterproof membrane and an impervious tile. They are there for a reason.
FWIW, most internal walls are not load bearing, and it makes little difference what is applied to them. A properly installed sheet of Kerdiboard, covered in tile isn't going to make your house fall down in an earthquake!