The idea is a mobile pillbox, but pillboxes need to be really heavy because they don't move very quickly. This can't carry three feet of sandbags around, so if it gets hit with anything more than a light machine gun it'll go right through.
It's slow and only effective against really light infantry. Though I imagine some kids with molotovs could make that guy's life hell for a few minutes so I don't think it's even effective against light infantry.
Plus it's tracked and underpowered so it's probably a pain to haul around, slow, noisy for the driver, and the excavation tools in the front makes me think it's not that great over rough terrain.
Armor steel (STS) was developed in 1910, so I looked into this thing a little more and found the link above.
The armor had some decent stopping power and was rated for Mauser AP rounds in the front and regular service rifles (ball rounds) in the sides. Both ratings were for projectiles being shot at 90Β°, so that is fairly significant. (Any other angle, the energy of the projectile causes it to deflect.)