Hi, I have seen several times online examples of wallets where lined leather isn't stitched, but simply glued on the open side of a pocket. An example can be seen here: https://www.reddit.com/gallery/j0w0wd You can see the pink lining is simply glued on that exposed edge to the main leather.
I think in this example edge paint may have been used. But I have seen examples without edge paint. Without the edge paint wouldn't the layers risk splitting apart?
Could simple glue and burnishing hold 2 layers of leather together reliably?