Most chromebooks don't have replaceable storage. Acer seems to be the only one making new chromebooks with replaceable storage. Also, eMMC isn't an SSD
Sure, but the Pixel last year did not have a replaceable SSD, only some of the cheaper/slower models did. I don't know if this one does.
Not anymore, almost all of them today are based on Intel's SoC architecture that can use embedded eMMC memory (basically a SD card on a chip) instead of a SATA SSD that you can replace. It's a cost cutting thing.