Any 120v connection needs to be made in a suitable junction box. This may be a separate box, as in a wall outlet or switch box, but it may also be a box integral to an appliance or power supply. On the other side of the power supply, low voltage lines (12v, 24v) do not require junction boxes, but should still be made in a workmanlike manner.

Whipping is a separate power cord from each appliance back to the power supply. In contrast, daisy chain has one power line and each fixture taps power off as the power line passes by. The difference is daisy chain experiences increased voltage drop along the line as more fixtures are added; theoretically the first fixture will receive full voltage while the ensuing fixtures each receive lower and lower voltages. The current draw of each fixture determines how big of an issue this is. In the world of LED lighting, either wiring scenario should work fine as the LED current draw is now much less than the typical current draw of the old style bulbs. Your electricians may be promoting whipping due to the inertia of their training and experience. If they looked at the actual numbers they might see that it isn't an issue with LED lighting like it used to be.

Thank you. Much appreciated.

This hypothetical is curious.

Imagine a dropped kitchen ceiling with 24, or many more, wafer LED recessed lights being installed.

You wouldn't be able to whip that many MC wires out of a single junction box. Setting aside the available punch outs, I'm guessing even the biggest connectors have a limit on how many wire can be twisted together inside the cap.

So... if an electrician was not going to daisy chain the lights, how would one go about the configuration?

Just add more junction boxes?

In that case, all the junction boxes would have to be accessible, and that would clutter up the ceiling with cover plates?

Or, in the case of a kitchen, the other junction boxes would be made accessible behind the top wall cabinets?

Separate question:
How many MC wires can fit/twist in the biggest connectors anyway?

If you're whipping, and running 4 MC cables (4 LED light fixtures) into a large box, can a single screw connector fit the hot wire and the 4 other wires?

I'm thinking this whipping has a limit because of the ability to splice more wires, whereas the daisy chain's limit is the power draw.

Thanks.

Re: Your example - "Imagine a dropped kitchen ceiling with 24, or many more, wafer LED recessed lights being installed."

- The majority of LED bulbs/fixtures for can lights or ceiling applications are retrofit or new work 120v devices. The fixtures themselves will have built-in junction boxes, so most electricians will daisy chain them along the Romex because that is a fast install. 120V LED dimmers that fit standard junction boxes are readily available and reasonably priced, so this is a plus as well. How many wires can be connected together is not just a matter of the wire nut size being used, but also depends on junction box volume requirements by code. Most junction boxes, either electrician mounted or on-fixture boxes, are properly sized to accept two #14 Romex cables, so daisy-chaining is kind of a no-brainer as the easiest installation route.

- If the bulbs/fixtures are low voltage devices, the system typically has a step-down transformer or switching power supply and associated low voltage wiring. On the low voltage side code does not require junction boxes, etc., at a minimum, wire-nutted and exposed wires are acceptable. Many vendors will use proprietary connectors and mountings to make a complete system available to the consumer. These typically are whipped (albeit with short leads) back to a common power bus (low-voltage daisy-chaining). I'm thinking here of in-cabinet or undercabinet lighting, art lighting, etc.