Why is this "slow move" with the king a good move? rn1qkb1r/1p3pnp/p1p1p1p1/3pP3/3P2P1/2NBBQ1P/PPP2P2/2KR3R w kq - 0 13

Stockfish (depth 30) says the best move is Kb1 with +1.5 evaluation.
I'm having trouble to understand why.
The a2 pawn is not getting threatened soon,
and that the c1-h6 diagonal is well guarded against checks.
Furthermore, it is early game and white has an advantage,
building pressure on black's kingside. Kb1 looks like a tempo wasting move
that just doesn't accomplish much.
The engine also likes Qg3, Ne2 and Bh6, which I deem more active ones.
But can you help me understanding reasons why Kb1 is a good move?
Just because Stockfish thinks a move is best doesn't mean it is best. But let's see why Stockfish might like it.
When I look at Stockfish's static evaluation of that position, and move the king from  c1 to b1, I see four sub-evaluations change. In order of the size of the change, those sub-evaluations are:

Psqt bonus. This gives a bonus to each piece based on what square it's on. The king gets a bigger bonus simply by being on b1 instead of c1.

Shelter weakness. The king gets a penalty on c1 because the adjacent d-pawn has moved, and gets no penalty on b1 because none of its adjacent pawns have moved.

Mobility bonus. On b1, the White pieces are slightly more mobile (the rooks can now move to c1 - yes, it counts the square for both rooks) and that gives a bonus.

Shelter storm. Black gets a bonus for the d5 pawn beginning to &quot;storm&quot; the White king if the king is on c1. With the king on b1, the d-pawn does not count as &quot;storming&quot; since it's no longer on an adjacent file to the king, and Black doesn't get this bonus.


All told, it adds up to about 0.5 evaluation points.
It seems that Stockfish is simply having a hard time coming up with a good plan here. At depth 27 it gives Rhf1 as the second-best move, but the line it gives starts with this.
rn1qkb1r/1p3pnp/p1p1p1p1/3pP3/3P2P1/2NBBQ1P/PPP2P2/2KR3R w kq - 0 13

1. Rhf1 Nd7 2. Kb1 a5 3. Rg1

But it doesn't exactly seem like the best sequence for making progress.