This fine fellow was an attractive cause for some amusement at Baddesley Clinton (a National Trust property near us) a few years ago. He really does make one wonder how effective he is, as he is far from being scary for you or me..
But it may well be different for the crows, for whom he is the intended deterrent. Scarecrow is different, alien and, perhaps, enough to frighten the birds.
I then wonder about all those people who are 'scary' to us simply because they are different? We can be nervous of people of a different nationality, language, colour of skin. Those whose behaviour, shaped by a different culture, may concern us or appear threatening. It may be that anyone who is 'unknown', and this might be our neighbour, encourages a caution in us simply because we a nervous of difference. Yet, how often do we overcome our caution, discovering that difference does not mean scary or threatening in reality?
Don't tell the crows, but it is good to realise that the scarecrow is indeed harmless and that the smile is genuine, even if he is a bit dishevelled and showing the marks of sleeping rough!