Are the performance of separates worth the price?

Absolutely not, if you consider that to do this right you would be adding the price of a good set of interconnects, two audio grade power cords vs one, rack space & footers, plus separate noise filtration for each separate component. It's simple mathematics.

It's like everything in life. While one may work perfectly fine, two are better. On the other hand, in audio, it may not be true. It depends on WHAT ONE or WHAT TWO you are considering purchasing. Obviously one Mark Levinson will be better than two Rotels. What will you be hooking them up to? $300.00 bookshelf speakers or $12000.00 floor standers? What is your aim? Ultimate fidelity in the ultimate system or less? I think you should buy what you can afford and then a little bit more. The only mistakes I have made in this hobby occurred when I got cheap and did not get what I wanted.

Please give us some more info. on the specific components involved. You really need to compare model by model w/in a given Mfg's line-up. And knowing the rest of your system would be very helpful also. Also your budget, your tolerance for complexity, possible WAF, etc. (IMO, your question is so theoretical it's very hard to answer).

I saw from your previous threads you were considering purchase of the BAT integrated. Is that still the case?

With separates you have flexibility. With an integrated, if you want to change anything, in many cases you have to sell it & start over. I've never heard really expensive integrateds like the BAT, or the Rowland, but if it were me, in that price range, I'd go for separates.

But, if you are new to the hobby perhaps, or if there were another factor like someone else using the system who didn't understand turning on or off many components, an integrated could make lots of sense, esp. to save $$. (I'm not inferring that an integrated is only for newbies--I've owned them & I know there are some that I'd drool over in certain applications). Just my 2 cents! Good luck.