It depends on what you mean by 'battlecruiser'.
Is it the original cruiser-killer - a really big cruiser armed with battleship scale weapons, with cruiser speed and just enough armour to deal with cruiser weapons?
Or the later versions that were light, fast capital ships with lighter armament (but still battleship grade), and lighter protection (but still enough to handle lighter capital ship weapons - like those on simliar BCs)?
Or super-fast 'speed is armour' almost no protection and battleship guns of Fisher's old age?
The above were all about the same displacement as a battleship, and often cost more.
Or the common SF 'battlecruiser' that's some sort of large cruiser/small battleship partway in-between them in size (as seen in Weber's
Honor Harrington novels, among others)?
Of the above only Fisher's insane things were ever intended to be part of the line of battle - and his were supposed to be all of it because they couldn't function if they were tied to a formation of slower ships.
Or the 'hero ship' version that's got the firepower of a battleship, the speed of a cruiser, and while it has less armour than a battleship it somehow beats them? These are often actually a more advanced 'next generation' battleship, and so probably are really the equivalent of the 'fast battleships' of the late 1930s, vs the older capital ships of WWI and just after.
I don't think any really work in an optimised
HG. Or rather, they do, but more armoured but slower battleship won't so there's nothing to contrast them with.
Some will work in other editions, though as with real life their cost-effectiveness is open to question, especially if the other side also has them.