I have an HP laptop (http://www8.hp.com/ca/en/products/laptops/product-detail.html?oid=1308672). I hope not mentioning it explicitly doesn't violate stackexchange's policy.
It uses eMMC as the main storage and has to SATA (mSATA) interface in the board at all. Even if one uses an external drive for their files, different softwares writing onto Window's pre-set temporary folders will cause the eMMC to be written over and over again. Eventually this will lead to the eMMC's shortened lifespan. After the eMMC has expired, the user will then have no choice but to run the whole OS on an external drive, if possible, even.
If they would use an eMMC for current market prices and low power consumption, why make it embedded and not swappable? I can't believe nobody is manufacturing eMMC modules that have mSATA. mSATA not small enough? Go for M.2