Is under-cabinet lighting worth it?

Almost every kitchen is lit from the ceiling, and almost every kitchen has the same flaw: when you stand at the counter to work, the ceiling light is behind you, and your own head and shoulders cast a shadow over exactly the spot you are looking at.

Brighter ceiling light does not fix it - it makes the shadow darker. What fixes it is light arriving from in front of you, above the counter. Wall cabinets happen to put a surface in exactly that position, and under-cabinet lighting uses it.

That is why, for most kitchens, it is the single highest-impact lighting change available. It is not decoration; it removes a shadow that has been there every time you have cooked.

You do not need an electrician to find out. The plug-in route gives you the full effect with no wiring, which means you can try it cheaply and keep it if you rent.

Enbrighten 18 in. plug-in bar - the easiest start. 1,245 lumens at CRI 92 with five color temperature settings and dimming built in. One under the cabinet above the counter you use most shows you the difference the first time you cook.
Cons: 18 inches covers one work zone, not a whole run.

GE 36 in. convertible bar - for a longer run. 3000K at CRI 90, linkable from one plug, so a whole counter can run from a single outlet.
Cons: no published lumen figure; stepped rather than stepless dimming.

WOBANE COB strip - for a seamless line. CRI 90+ at 3000K in a continuous emitter with no visible dots, which gives the most even line of light along a counter.
Cons: no published lumen figure.

Armacost PureVue puck - for specific spots. About 375 lumens per puck, for lighting a particular spot rather than a continuous run. Pucks light objects; bars light runs - see best LED puck lights.
Cons: needs a driver, and leaves gaps between pools on a long counter.

No wall cabinets. Under-cabinet lighting needs a cabinet to hide under. Without one, the equivalent is a pendant over the work area or a task light, covered in kitchen lighting.

Open shelving. A fixture under an open shelf is visible from across the room and shines at eye level - a glare source rather than a shadow fix. Mount it well back, behind a lip, or use a different approach.

A counter already lit from the front. If a well-placed pendant or window already lights the counter evenly from in front, the shadow problem may already be solved and the benefit is smaller.

For everyone else, the answer is yes - and the plug-in route means trying it costs very little. The full picks are in best under-cabinet lighting, and the strip-versus-bar decision is in strip vs puck vs bar.