Does UFS vs eMMC storage actually matter?

Yes, and where it matters is random I/O — the access pattern behind load times and texture streaming — not the sequential number a spec sheet leads with. On a device pushing PS2-era games and up, eMMC’s weaker random reads can bottleneck an otherwise-capable chip into stutters, while UFS keeps up. On a budget retro handheld running lighter systems, eMMC is fine, and a fast microSD carries much of the library either way. When two devices are close and one has UFS, that is a genuine point in its favor — buy the storage tier for the ceiling you intend to hit.