This is your core common, and it's clear why: it's built to protect your key units. In a summoner, and champion centric deck, that’s invaluable. Its Protect ability is already strong, but it also comes with one of the best abilities in the game: Shove. This helps both in defending your board and in pushing enemy units into your summoner’s range.
You’ll typically want one or two of these on the board at all times to make it harder for the opponent to reach your champions or summoner and to have some board control. Don’t hesitate to deploy them aggressively to accelerate your hand management, you’ll always find a use for them.