Regrowing lettuce from a stem: is it worth it?

I often grow spring onions from onion bulbs on the kitchen window sill. When I was a kid, seeing these bright green spikes on the window, in the middle of winter, when everything outside was buried under a thick layer of snow, seemed like a mini miracle.
During the recent lettuce-gate, when lettuces and courgettes seemed to be in short supply in many supermarkets, I thought: why don't I try to re-grow lettuce from the stem, as I have seen online before. My point of reference was a blog post How to regrow romaine lettuce on Getty Stewart's blog.
It will be an interesting experiment. Just how difficult might it be and is it really worth it?

I go through phases, of when I crave fresh lettuce, and will happily eat it for lunch every day for a couple of weeks, then I lose any enthusiasm for it until the next time I fancy it again. Munching trough a small head of lettuce every day, I had plenty of material to play with, both cos and gem lettuce varieties.

The instructions seem to be pretty simple:
Take a fresh lettuce (cos, romaine or gem), and cut off the bottom part/stem at about 3-4cm high.
Place the cut off part into a shallow dish or cup, filled with water. Water must reach at about half way up the stem.
Place the dishes on the window sill, where there will be a bit of sunlight.
You will need to change water every couple of days.
In the first couple of days nothing is happening, but then you will notice new tiny shoots appearing in the middle of the stem.
Wait for about two weeks for some leaves to develop "properly". Don't expect a lot of salad.

This is the result of re-growing lettuce for 15 days or so. I have waited for another week to see if it is going to grow more, but the difference was minimal.
Enough to add to a bowl of salad with lots of other ingredients, or in a sandwich, though not for a whole family.
It was a fun experiment, and you might like to do it with children. This is also a lesson on patience.

Is it worth it? perhaps not, though you get some food for nothing.

Have you tried re-growing lettuce from a stem?