is every expensive preamp worth it? no.
do some deliver the goods? sure they do.
i have 'one of those' over $20k preamps with built-in phono stage. it's too bad it's sounds better than less expensive pre's, or even other expensive pre's, but it does.
it's swiss made, battery powered, and i've owned it for 5 years. i've compared it directly to quite a few stand alone phono stages and other pre's. it sounds better.
Michael Fremer has had the same pre for 3 years and compared it to 4 or 5 equally or more expensive pre's and only one (more expensive) was it's match....if somewhat different.
sure; the Swiss franc and the dollar is part of the issue. but it's assembled like a swiss watch....and then there is how it sounds (or rather does not sound).
and if you are asking 'where's the value?' you need to listen to it in a system which can show what it can do, maybe open it up and look at how it is assembled. use it for awhile to see how everything works exactly like you might want it to.
in the context of a top level system a no-holds-bared preamp does earn it's place. unless you have very low noise sources, a good turntable, arm and cartridge which can take full advantage of the low noise switching and attenuation, you nmight not get the full value of the refinement of the top of the food chain.