It is necessary to tuned regularly. It is helps in reducing false positives and keep the signatures latest and optimal.

It can lead to loss of governance.
In using cloud infrastructures, the client necessarily cedes control to the cloud service provider(CSP) on several issues which may affect security.
The loss of governance and control could have a potentially severe impact on the organization's strategy and therefore on the capacity to meet its mission and goals. The loss of control and governance could lead to the impossibility of complying with the security requirements, a lack of confidentiality, integrity and availability of data, and a deterioration of performance and quality of service, not to mention the introduction of compliance challenges.
Source: ENISA- Security Risk and Benefits