Ausatco
I cannot see the value in a landing clearance when the landing area is clearly not clear, if you see what I mean
I, too, clearly share your clear concerns in this regard. Let us examine the recent Brisbane incident:
1) The aircraft calls the tower. Perhaps the call was acknowledged, I am not sure. Either way, a landing clearnce was not succesfully issued on first contact.
2) The aircraft continued approach, as cleared.
3) Tower attempted to issue a landing clearance, but was blocked by another transmission.
4) Despite a clear runway ahead, the 'anally retentive' pilot elected to go around, thus ensuring both the safety of the aircraft and compliance with the last received clearance.
Result: A technical 'incident' and the extra cost of a go around to the airline.
Now, let us imagine a similar scenario, but where a clearance is issued in advance:
1) The aircraft calls the tower and is issued a landing clearance, despuite the fact that a vehivle is still on the runway (on SMC frequency).
2) The aircraft continues approach and sets up for a cleared landing.
3) Noting that the vehicle has failed to clear the runway, the tower attempts to issue a go around instruction,
but the transmission is blocked
4) The aircraft lands and collides with the vehicle.
Result: A collision.
Like Ausatco, I do not see the 'value' in an early landing clearance. It merely strips away one of the layers of safety which are designed to prevent collisions. If there is a sound reason which justifies this method, I have yet to hear it. Perhaps our US colleagues canb enlighten us.
What concerns me here is 'mindset' or 'confirmation bias'. A pilot who has not been issued with a clearance is more likely to continue the approach with a 'go/no go' mindset. That is, they will have a 'plan B' which will be something like: "If not cleared to land by xxxFT, I will call short final. If still not cleared, I will go around." This would be one more opportunity for both controller and pilot to ensure that the landing will be safe. If it goes wrong, the cost will, as in the BN incident, be economic.
On the other hand, a pliot who has been cleared to land will have a landing 'mindset'. ANy subsequent go around instruction will involve a late
change to this mindset. That is, the go around will be a change of plan, as opposed to the selecxtion of an already existing plan.
I realise that, on first reading this, some pilots will take this as a slight on their professionalism and their adaptability to all situations. It is not intended as such, and I apologise in advance.
My point is that all humans (and I include pilots in that definition 
) are subject to certain ways of thinking. It is not hard to find instances of 'mindset' which has led to disasters. For example, the Air Inter crew who set a 3,3000fpm ROD, believing it to be a 3.3 degree AOD. The point is that the system must be designed to be as error tolerant as we can make it.