I've always liked the SRE approach, where you can alleviate software engineers to build new features without burdening the team with 24/7 on call duties.
SRE/Ops person here. SRE only works if SRE can look at software and go "Nope, it's not ready for production and I don't care how wanted this feature is." Almost no company is mature enough to allow that behavior.
Same. SRE is generally code for “we need cloud sysadmins but that’s not fashionable anymore.”