What advantages are there to painting the inside of the block?

No such thing as a dumb question if you really want to know the answer to it ..........and I wanna know ...........What advantages are there to painting the inside of the block? besides faster oil return?????????? Would it not make the block retain more heat internally as paint is a insulator so what big advantage is there???????? On a drag race only engine the faster oil return to the sump ----I see advantages ...... What type of paint does one use inside the block that will adhere to the metal?????? Block prep would be a major job protecting lifter bores etc.....
I have toyed with the idea of painting the inside of the block on my 70 model 340 which is still in the machine shop and is not yet finished.................. the lack of heat dissipation would keep me from it for a street engine....... Please advise old wise one..........Texas Red... Gary