We use it as usual, multilayered exr render > Comp on Fusion with automatic meshID.
This step help us to avoid prerender the mattes of every single mesh.
In most cases Compositors in production request RGBA mattes for CG elements from the CG Artists. Depending on the complexity of the scene this could become quite the task as your limited to 4 channels per image. you can spend hours if not days of artists time creating mattes for comp. Cryptomattes eliminates all of that by providing one pass that includes a matte for everything that is rendered.
Andy (one of the creators of cryptomatte) added some info about integration on Cycles, may be you like to take a look ?