Perhaps we should all consider this more than we do. One colleague of mine is only interested in one thing - his house. If he loses the equipment, he is insured, but the house, despite being insured, is his home and he does not want to have to move and start again - which most big fires usually mean.
His fear is that the external metalwork creates a path into his house, and once there, it does the damage. Joining all the grounds together makes the access even better.
In audio and video entertainment where I work, ground loops are one of our big problems. PA systems hum and the big video walls have hum bars running up and down them when people ground things randomly to 'ensure safety'.
At events, festivals and theatres we had a long term problem with the front of house mixers - if they derived their power locally, from a handy socket, very often terrible hum was the result. The earth in the audience and the earth on stage were many metres apart, and both a different reference voltage - sometimes you'd have more than 5v difference, and this 50Hz voltage would 'leak' into the sensitive audio kit and huge hums were the result. The solution was to run a very long cable from stage to the back so the audio system all got it's power and grounding from the same place. Now it's not a problem anymore because we have a fibre optic cable doing the job, but for years this has been a real pain. Worse - unskilled people would remove the earth wire from the plug, to cure the problem. Then things would go wrong and microphones would become live - nasty.
We started with lightning, but the problems of grounding in the shack are the same - multiple earths can cause unintentional problems.