Gravity only working when physics enabled?

I have an actor with a collision sphere as root component, and a skeletal mesh attached to it. Both components have gravity enabled in their details/settings.
The actor starts in the air, i.e. a few units above the ground plane.

Now when I run the game nothing happens, the actor stays “floating” on its spawning position.
However, when I enable physics for one of the two components and run the game, then the actor correctly falls down to the ground.

From the third person example I can see that the player character gravity works even without physics enabled.
Unfortunately I cannot find the difference between the example and my custom actor.

Any ideas where I could look for the cause of this issue?

Pawns and Characters are moved by a MovementComponent. This is a special component that can be used to make actors move. They are using different movement code that is more fit for gameplay than the phyiscs simulation it also enables a programmer to program pseudo-physics, etc. They also have some additional functionality in regards of networking like prediction to make the movement feel better to the player controlling the Character.

So to make an actor move, you can either move them with phyiscs or a movement component (or other means of coding the movement for your actor).

Thanks for your reply. Does that mean that also the gravity is simulated by the MovementComponent?