If your argument holds true why bother with high intensity lighting on top of buildings like Canary Wharf far easier to see than a pencil thin crane towering into the clouds above it?
1) See what SLFandProud said above ....
So what happens when the extra hole in the cheese lines up, and the battery fails, or the xenon tube blows, or the wind takes the antenna off the transponder, or whatever? Accident still happens.
2) We're potentially talking about a scud-running scenario here..... what good are flashing lights during scud-running where cloud/fog cover is ever changing and you've basically already put yourself (accidentally or otherwise) into a situation where there's no obvious route out because the weather has trapped you in.
Surely the safest thing to do in that context, particularly if you are in a helicopter is just to stop and put it down in the nearest safest spot...... isn't that one of the main benefits of a heli ?