The Skyraider was built to have the ability to loiter and drop a lot of ordinance, they were able to absorb tons of damage on Ground Support missions. They knew they would take a lot of hits, OV-10 and A29 are not built as attack aircraft in contested air space.
No. The Skyraider was designed as a dive/ torpedo bomber for the US Navy; CAS was secondary (and a function of its first war in Korea). The USAF adopted it much later.