That’s correct, the main difference is centered around setting up ESXi Embedded so that it doesn’t do lots of writes. This is because ESXi embedded is designed to be installed onto SD Cards and USB sticks, which only have a limited number of writes compared to magnetic storage such as hard drives.
In ESXi Embedded, the log and temporary file locations that have frequent writes are moved to RAM instead of the hard disk. This means that they can be lost in the event of a crash or reboot. Although, it is possible to create a scratch location for these files on a SAN or send them to a syslog server.
Incidentally, you don’t get to chose whether you install ESXi Embedded or Installable, ESXi will automatically give you the right type of installation depending on you partition size. ESXi Embedded will automatically be chosen if your install destination has less than 5GB of space.