Nodes can't be compensated for this— only the single miner who chose to burden the chain with the contract. Everyone else has to go along for the ride (or skip verifying it and hope that the anonymous miner wasn't lying). This is one of the reasons Bitcoin has very purposefully eschewed contracts which are computationally expensive to execute.
You can almost always perform a computationally expensive contract externally to the system and bind it with a hashlock or multisig, in any case. The inability of the a consensus system to perform IO to outside world usually demands those techniques in any case.
Imagine someone develops a chip that can calculate ECDSA operations 10 times faster, consuming 100 times less electricity. In a well-functioning market, the consequence of this would be that the price of ECDSA operations would drop, to reflect the fact that they now cost less to verify. With fixed fees, this isn't possible, and there is no financial incentive to optimize any given operation, without optimizing all operations simultaneously.
Such a network can grow to some extent, but how can it truly scale? There is limited scaling, of course, but node requirements increase as traffic increases, and there is no scalability through distribution of computational resources. So the more work the system does, the stronger each node needs to be.
If the answer to this is, "No problem - we'll just make it more expensive," then the required computational resources could be purchased with the very cryptocurrency that is generated from the system. At that point, it seems to me that the snake eats its own tail.
Regardless, before we declare that there can be any democratization enabled by this tech, I think we need to ask the question, "How does this not transfer even more power to those with the most computational power?"
Put another way, it seems this is tailor-made for Google and Amazon, not an organization of Joe Publics, each with a couple extra GPU's installed. It's still going to be about the "haves" and the "have-nots."
I'm happy to be proven wrong on any of these thoughts. I just think that if we were talking about any other tech, this computational model would not be considered scalable in any meaningful way.
Now try calling some lawyers and ask them how much it typicaly costs to defend a contract in our traditional court system... it will probably be a number 100000% higher than 50 cents.
Cryptocontracts are great for Joe Publics.
From there you can write contracts that do things similar to their paper, real-world counterparts. Say you wanted to set up a one-year rental contract. The landlord would create the contract and you, the tenant, would transfer your security deposit into it. The contract would have logic something like this whenever it is activated:
if rent money was just deposited
transfer the money to the landlord
mark last month as paid
else if payment is more than 30 days overdue
transfer security deposit to landlord
end contract
else if one year has elapsed since contract started
transfer security deposit to tenant
end contract
The idea is that instead of a contract being enforced by the good will of the participants, or a court if that fails, it's enforced by the logic programmed into the contract itself.
This ignores the reason for a deposit in the first place. What if the carpets were burned in that year? Some of the deposit needs to be kept by the landlord. How does etherium know the carpet was burned? If the landlord says so, then the landlord may be lying.
For simpler operation - if rent not paid - then end contract - that sounds like it adds no benefit. No need for a program to tell you the contract has ended.
This is very useful to prove authenticity of a contract and for very simple contracts as well such as a bet. If there can be any sort of dispute about the contract though I don't see how it can be useful again save for authenticity.