Even though Lou Ferrigno voiced Hulk in early MCU films and even appeared through a live-action cameo, he is not shy about expressing his distaste for some of the choices Marvel has made concerning his beloved character.
Even so, he’s got to admit that times have changed quite a bit since he played the character and that CGI is sometimes pretty necessary.
So without CGI, their Hulked out selves wouldn’t be as incredible.
I mean, Mark Ruffalo isn’t as buff as Ferrigno was and Tatiana Maslany is no bodybuilder, either (although Marvel actors tend to become pretty built the longer they are with the MCU).