In message , Set Square
writes

However, I'm faced with the question "Why would anyone conceivably *want* to
replace a conventional boiler with a combi?"

Space was the short answer for us.

We replaced our boiler/HW tank system (the boiler was old and getting
knackered) with a combi.

We had a small bathroom , by getting rid of the tank and airing cupboard
we were able to put in decent separate shower, and rearrange things to
make a much better room. One advantage of the combi of course is we get
a good shower as well with no pumps etc.

Yes, I miss the airing cupboard at times, but I don't really miss the HW
tank that much. We are mostly shower people, and don't run baths very
often so the slow flow rate of the combi isn't to much of an issue - the
mains pressure HW is benefit. Multiple draw offs aren't a problem for
us.

It's not perfect, it's a compromise, but one that works ok for us.
--
Chris French, Leeds