Your PC probably doesn’t need both ports, but workstations and servers can put them to work.
The two Ethernet ports on some PCs aren't a matter of aesthetics or a simple selling point. Their primary purpose is to provide the computer with more networking options, like backup connections or separate networks. If it's configured for failover and you lose a network connection on one, you still have access through the other. In most cases, it's a feature that's primarily relevant for workstations, servers or virtualization setups. Your home internet likely doesn't go out often enough to justify paying for a second connection you only need when the first is unavailable.
Dual ports can also support link aggregation (sometimes called NIC teaming or bonding). Put simply, link aggregation allows the PC (and a managed switch, in some setups) to combine two Ethernet links into a single connection. This has the added benefit of boosting bandwidth while maintaining the aforementioned redundancy.
Don't expect two Ethernet to magically double your internet plan; you're not going from 1 Gbps down to 2 Gbps. Link aggregation has to be supported and configured on both ends, and while you can share the extra capacity, data transfer generally remains limited to the speed of one link.
The most useful benefit of two Ethernet ports is network versatility, especially with everything Ethernet cables can do . For example, one port can connect to your regular home network, while the other can connect to a local network (like industrial equipment in a laboratory) or a dedicated storage drive.
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