It’s a must-have! And Watchdogs are great. I have the Progressive Industries EMS, but the Bluetooth feature on that Watchdog is a nice feature. I also prefer the hardwired version as opposed to the portable version. One less thing to do (and forget) during setup and it’s way less likely to be stolen.
I didn’t fully investigate the one you pictured, but I’d step up to the version with EPO or go with the one @tory-jon mentioned. The one you pictured looks to only protect against surges, while the EPO adds low power protection, which is just as bad as a surge.
I’ve been saved from low power at campgrounds at least twice that i can remember. The damage that would have caused would far outweigh the cost of getting a surge protector with epo