What's the difference between type of device options?

[Brix1330]

For instance there's two choices when I add a smart plug: smartplugv2 and smartplugv2_polled_power.

[make-all]

The second one will poll the inputs for power/current/voltage every 30s.

Some smartplugs do not update those values automatically, so need to poll with a special command to force updates.
Other smartplugs do update automatically, and don't like the command to force updates (going offline/rebooting if it is given).

[make-all]

Try the smartplugv2 config first. If you see the power / current react within a few seconds of changing the load, then that will be the best config to use. If it takes 5, 10, 30 minutes, or you never see a change, then you probably need smartplugv2_polled_power, so delete your device and set it up again with that config.