Functionally identical to a radio group — exactly one segment is selected at a time. Wrap it in role="radiogroup" with role="radio" and aria-checked on each button, or hide native radio inputs visually and style their labels as buttons.
The difference from tabs was covered above: tabs read as navigation that fully swaps a content area and sit at the top of a container, while a segmented control floats independently like a button group and switches a view state on the same screen — "Daily / Weekly / Monthly."
The sliding pill background only needs transform: translateX, but if the segment count can change, each segment's width (100% / N) has to be recalculated too.