CE can still be mostly run off of the eMMC on any box even the s905x4 with this guide.
The CE eMMC tool resizes and creates partitions. The guide above only moves all of storage to the eMMC data partition. The kernel was already being loaded and run from RAM. That only leaves a portion of the system.img running partly from USB and RAM. This setup gives you most of the benefits of the CE eMMC tool.
It does still require the USB for booting.