Maz - Look/Time are slightly different systems but they are basically designed for pedalling
not for walking! The shoes you use them with typically have very stiff soles and whacking great slippery pieces of plastic bolted onto the bottom of them! SPD cleats are fitted into recesses in SPD shoes so you can walk on the tread of the shoes rather than the cleats (although they can still be slippery offroad if you are clambering over rocks).
Those are Look type.
Those are SPD type.
See what I mean
?
I have Look pedals on my 'best' bike (my Cannondale) and wear a good pair of SIDI shoes when riding that. I wear cheap ALDI SPD shoes for my 'knockabout' bike (my Basso) which has SPD pedals. Ditto my MTB.
I agree that Look are 'better' than SPD in terms of support for the foot. I have more problems with my feet when using SPDs than using Look. Having said that, when I'm slim and fit I have to put about 20% less pressure on the pedals and don't have much trouble with either pedal system.
SPDs are much more convenient off the bike. If you spend 99.xx% of your time on the bike, perhaps you don't need SPD. I do a fair amount of wandering about at audax controls, toilets and cafes so SPDs come in handy. They are
much better when doing emergency dismounts on greasy wet 25% pennine hills.
Walking up that in the rain was a right bastard in my SIDI shoes with Look cleats