Here's my modified version of the example, it only moves the angle of your view, but it's smoother.

if !CLIENT then return end
require("faceapi")
function faceAPI_demoCalcView(pl, pos, angles, fov)
lastHeadAng = lastHeadAng or angles
local headAng = faceAPI.GetHeadAng()
local newHeadAng = Angle(faceAPI.GetHeadAng().p*3,faceAPI.GetHeadAng().y*3,faceAPI.GetHeadAng().r)
local finalHeadAng = LerpAngle(0.05,lastHeadAng,newHeadAng)
local WorldPos,WorldAng = LocalToWorld(faceAPI.GetHeadPos()*300+Vector(130,0,0),finalHeadAng,pos,angles)
// I add 130 forward since faceAPI's head center is a bit too close.
local view = {}
view.origin = pos
view.angles = WorldAng
view.fov = fov
lastHeadAng = finalHeadAng
return view
end
hook.Add("CalcView", "faceAPI_demoCalcView", faceAPI_demoCalcView)