You should never have to apologize for delivering value - that's ultimately the purpose of technology. If it's the cleanest/simplest solution to a given requirement, implement it and move on - don't worry about trying to appease cargo cults. Technology should be used as a tool to deliver the best value you can within a given set of requirements. End users don't care how many Internet points from fashionable tech du jour you collect along the way, all that matters to them is the end user experience, invest your energy towards that.

There's nothing wrong with RPC APIs. Other than being "Not Cool" due to the legacy of SOAP, they can deliver some very nice value.

Various RPC mechanisms like Bond and Protocol Buffers (and more recently GRPC) are trying hard to make RPC cool again. Personally, I hope they succeed, as REST (like any technology) doesn't work for everything.