It depends on your needs and use. I have SD cards in both.
The base backs up all my triggered event recordings so they last longer than 14 days (which is the limit for the cloud storage), and makes sure I can view what happened if someone tries to steal the camera (then I have a personally saved physical copy).
I have an SD card in the WCO itself because I like to use it for more than just motion events. I do timelapse recording with it, scheduled recordings that are much longer than 12 seconds, I take it hiking and other places with me in travel mode and use it to record the trip (both scheduled recording and time-lapse simultaneously), and all sorts of things.
You don’t even need an SD card in either of them if you just want to rely on the 14 days of cloud storage.
WCO is awesome in that the event cooldown period can be reduced down to 1 minute. I have one pointing right at my back door and it tells me everytime someone comes in or out our backdoor, and sends me a great thumbnail and 12 second recording. Works perfectly there. I also don’t have any lights or wires that get to the right spot, so rather than do some funky installation to wire a camera there, I just use a WCO and it is perfect there.
I’ve also used the WCO for temporary convenience to watch a certain location temporarily, or timelapse something while I do a temporary job around the house (I recently recorded timelapses for me digging huge holes and installing new windows in our basement with new windowsills, etc so we can legally say we have 2 more bedrooms than it previously appraised for…it’s cool watching the timelapse of the total change from how it used to be, to having huge holes, installing the new windows, adding the sills, and filling the dirt back in…I love it…didn’t need to keep the WCO after the project was done though.).
It is super convenient in many scenarios. Sometimes if when we are having our daughter babysit, we’ll move a WCO into a place where we don’t normally need or use Cameras, but with the WCO we can check in live on that spot anytime while we’re away. There are tons of great uses.
In the end, if you want a permanent 24/7 recording option or something that records for long periods of time (though you can do this on the WCO with CamPlus), then this is probably not the product you are looking for. That doesn’t make it worthless, it just means you are trying to use it for something other than what it was designed for and you should get a V3 or something else instead. It’s really that simple…WCO was designed for specific things. It’s still a great camera for those who use it for the needs it was designed to fit.