Yes they are two different products but as you mentioned they can work together (and in some features of SCC Enterprise Tier they do, out of the box).

SecOps is a SIEM and SOAR platform designed to retain, analyze, and search the large amounts of security and network telemetry your network and security infrastructure generate. Google SecOps normalizes, indexes, correlates, and analyzes the data to provide instant analysis and context on risky activity. Google SecOps can be used to detect threats, investigate the scope and cause of those threats, and provide remediation using prebuilt integrations with enterprise workflow, response, and orchestration platforms. The detections are normally created by pre-defined rules and searches based on the log data and information received from the sources like Firewalls, Proxies, EDR, Flow Logs, Authentication Logs, etc

SCC is comprehensive security and risk management platform designed to identify threats and vulnerabilities in your cloud environments. While SIEM tools normally relies on log data, SCC relies on a combination of things which a SIEM tool would not be able to detect normally. Few examples below:

- Misconfigurations: SCC actively looks for your cloud resources and checks for insecure configurations and also maps these for compliance standards (eg: Service Accounts with Excessive permissions, Open ports on your security controls, default service accounts used, etc) and provides you with recommendations on how to fix these

- VM and Container Threat Detection: VM Threat Detection detects potentially malicious applications, such as cryptocurrency mining software, kernel-mode rootkits, and malware running in compromised cloud environments. Container Threat Detection detects the most common container runtime attacks and alerts you in Security Command Center and, optionally, in Cloud Logging. Container Threat Detection includes several detection capabilities, including suspicious binaries and libraries, and uses natural language processing (NLP) to detect malicious bash scripts.

- Manage Vulnerabilities: Security Command Center provides comprehensive vulnerability detection, automatically scanning the resources in your environment for software vulnerabilities, misconfigurations, and other types of security issues that might expose you to attack. Together, these type of issues are referred to collectively as vulnerabilities.

There are lot more features within SCC depending on which Tier you are signed up for. I won't go into too much details but you can find some more information on the different features for each tier here.

As mentioned at the beginning both tools can (and should) work together. Normally i would recommend sending a select type of Findings generated by SCC into a SIEM+SOAR tool so you can perform further analysis of the alerts, correlate them with other log sources and create/run playbooks on certain alerts with your SOAR component. The integration between SCC and SecOps can be done natively and if you are signed up for the SCC Enterprise Service Tier, then this comes with an instance of SecOps which can be used to expand the features of SCC with SecOps features.