A coffee scale looks like an ordinary kitchen scale with a stopwatch bolted on. The integration matters more than it appears, because brewing coffee is one of the few kitchen tasks where weight and time have to be tracked simultaneously and continuously.
In a pour-over, you are pouring water while watching the weight climb toward a target and tracking elapsed time against the brewing schedule. Doing that with a scale in one place and a phone timer in another means looking in two directions during the one operation that needs attention.
A single display showing both removes the problem entirely. Scales built for this, including the coffee-specific models in the Escali Scale range, put weight and elapsed time side by side and start the timer with the first drop of water.
This is the specification that separates a coffee scale from a kitchen scale. A general scale updates its display slowly and applies filtering to give a stable reading, which is ideal for weighing flour and useless for pouring.
A scale that lags behind the pour means overshooting the target, which cannot be undone. Fast response is why dedicated coffee scales exist.
For espresso the scale sits on the drip tray under the cup, which imposes size constraints and exposes it to heat, steam and drips.
Weighing the yield rather than judging by volume is the single biggest improvement most home espresso setups can make, since crema makes volume an unreliable indicator. A shot that looks correct can be substantially under or over the target weight.
Place the brewer on the scale, add the filter, rinse it, discard the water and tare. Add ground coffee and note the dose. Tare again. Start pouring, and the timer begins.
Everything happens in one place with one display, which is the entire argument for the integrated design.
For anyone brewing filter coffee daily and wanting consistency, yes, and the improvement is immediate. For someone using a capsule machine or a drip filter with a fixed basket, no, since the variables are already fixed.
A general kitchen scale plus a phone timer works and is less convenient. Whether that inconvenience justifies a second scale depends on how often you brew and how much the consistency matters to you.