Well the first eSIM devices where smartwatches(Gear S2) and they used the lower powered SOC and the core design was from previously used smartphone SOC. Physical SIM cards where hard to package into a smartwatch, hence the introduction of eSIM. Also smartwatches have much lower profit margin, hence the reason they use older process node and no one wanted spend money on integrating it into SOC when they can use an older smartphone SOC design.