Advantages of using Code-pipeline and Codebuild for CI/CD over Bitbucket pipeline?
A bit too long for a comment, so converting to an answer:
That's super broad and highly depends on your final needs IMHO, if you're full AWS and ok with being vendor locked down, then code commit/code build/code pipeline is great as it's nicely integrated now.
If you have needs outside pure AWS services, that may get harder, for exemple if you plan on stretching on multiple cloud vendors in a always on DRP (Disaster Recovery Plan), that's probably not the better tool.
My take is that for a full AWS things, AWS products are good and usually soften the edges, but if you need to interact with things out of AWS, there's solution more aimed at CI/CD like Bitbucket, as you said but that'd be my last choice, CircleCi, Travis, Github Actions and Gitlab.
The CI/CD cost is rarely a concern, even if you have a super large company with dozens of products, the code repository and user management costs will probably out-stand the pipeline costs by a large factor unless you run thousands of pipelines per day.
My personal preference goes to Gitlab for its versatility in pipelines, how easy internal runners are to setup and to avoid vendor lock down on the hosting.