That's subjective, and depends on local road conditions. Good for you if that's enough for you, but some need more. The suspension travel is very short, and I wouldn't call it "comfortable" even with 44-355, but it's acceptable for me. There's also the safety aspect, wider tyres are safer with regards to cracks, holes, road debris, gravel-on-pavement, etc. Then there is the need for mudguards for practical riding, I don't know if 406 is possible with that.

This is the message anyone pondering 355 vs 406 should get: It depends on the rider and the road.