As everyone else is saying, power usage should be less this way. Probably less latency to traverse the switch than a software bridge, too. Switching should continue to function if the host OS crashes, combined with a watchdog and recovery, you could have a more available system where maybe some things don't work for a brief interval, but much better than a software bridge (assuming the switch chip doesn't crash or get stuck, anyway).
It depends on what your goals are though. If you want to inspect all traffic passing through the switch, having 4 interfaces is clearly better. If your host based switch is also doing a lot of communication, 4 interfaces gives you 4gbps from the hkst rather than 1gbps. Etc.
Ex-enterprise quad 1G cards are $15 or less on ebay. I'm partial to silicom quad bypass 1g_ PEG4BPI-SD; the bypass feature can be fun, and they're cheaper cause they're weird (you can mostly configure them to be 'standard nics' once and then plug them into anything without much fuss, but getting there can be challenging. Early ones come with pci ids set to silicom as the vendor and subvendor which makes them harder to use; the -SD cards have intel vendor id and silicom subvendor, so the normal driver will attach.
4x10g ports would be more to manage, and you might not have enough throughput for software bridging, depending on the host system. And quad port 10g cards are harder to find. 2x10G is reasonably priced though, if you're patient.
It depends on what your goals are though. If you want to inspect all traffic passing through the switch, having 4 interfaces is clearly better. If your host based switch is also doing a lot of communication, 4 interfaces gives you 4gbps from the hkst rather than 1gbps. Etc.
Ex-enterprise quad 1G cards are $15 or less on ebay. I'm partial to silicom quad bypass 1g_ PEG4BPI-SD; the bypass feature can be fun, and they're cheaper cause they're weird (you can mostly configure them to be 'standard nics' once and then plug them into anything without much fuss, but getting there can be challenging. Early ones come with pci ids set to silicom as the vendor and subvendor which makes them harder to use; the -SD cards have intel vendor id and silicom subvendor, so the normal driver will attach.
4x10g ports would be more to manage, and you might not have enough throughput for software bridging, depending on the host system. And quad port 10g cards are harder to find. 2x10G is reasonably priced though, if you're patient.