The big reason is weight I believe.
Next up would be saving a block with lifter bores that went south , and though you could simply bush them , I'd look at taking the next step as long as the wallet was open.
It gets expensive , though there are some screaming deals on used NASCAR stuff on the bay.........I got a set of lifters for very cheap , but had to send them back because they weren't drilled for pushrod oiling.
But they only had " dyno time " according to the ad , and they sure looked and rolled like new.
For 250.00 , that was a bargain.
Keyway bushings installed is around 800.00 I think , so it do get pricey.