2) To provide a battle shield to allow your districts to generate clones in 'peace'.

If you have only one district and it is underpopulated with clones then you can use an alt corp to launch an attack on your district. When the battle occurs, there is no real fighting and the attack fails. Net loss of launching the attack would currently be 40m - 200 * 50k = 40m - 10m = 30m. Essentially, you've ensured that the district generates 75 (or 100) clones for 30m. Expensive, but much better than risking a genuine attack where if you lose it costs you 150 clones and the isk to cover the equipment. Compared to a loss, your net gain is 225 (or 250) clone for 30m. This compares favourably to 200 clones for 40m from Genolution.

Notice how a reduction in the base district generation rate would actually INCREASE the need to protect yourself from attack using this method since you'll be vulnerable for longer (takes more days to get clones in the district up to a safe level).

Sorry, I think you have misunderstood how this works.
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Corp 2 (the alt corp) owns zero Districts.
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Final net cost to Corp 1 to 'buy' 75 clones is 30m. However since they have avoided the possibility of having a genuine battle (and losing 150 clones) you could view their net gain as 150 + 75 = 225 clones. This is even better value than a Genolution merc pack!