Peercoin's blockchain size is not 72% percent smaller, but Bitcoin's blockchain size is 72 times of Peercoin's blockchain size!
..or you could say that Peercoin's blockchain size is approximately 2% of Bitcoin's 
It's not only not self evident, but it depends on one's view as well.
Bitcoin will face problems due to its design. I can't foresee whether it can solve the problems. One remarkable point of time in the not very near but coming future will be the next block halving of Bitcoin in less than 100,000 blocks, occurring in roughly 90 weeks. With halved PoW block rewards (from 25 BTC/block to 12.5 BTC/block) operating miners that are running on knives edge (in terms of economical aspects) might sooner or later need to be turned off. The only thing that can prevent that from happen, is sufficient income with mining by a higher BTC price or more income due to way more transaction fees. It will be a dangerous time for Bitcoin. At the last block reward halving there was not this type of economy in place with data centres full of miners etc.
But that does not mean a majority doubts the sustainability of Bitcoin.
And although Peercoin is very great in terms of sustainability, because it can be maintained independent from both the Peercoin price and the number of transactions, it is yet so little recognized...
Something that compares Bitcoin's and Peercoin's blockchain stats might help people to get aware of differences between Peercoin and Bitcoin. Oh, it might make them aware that something like Peercoin does even exist!
It's not always the superior products that succeed. I hope in Peercoin's case that will be true and I consider Peercoin superior to Bitcoin in terms of sustainabilty. - but that's just a point of view; my point of view.
I think it leaves us with the chicken and egg problem.
Peercoin ATMs would be great to make people aware of Peercoin and to have easy access for buyers and sellers to the Peercoin network. But before somebody would invest in Peercoin ATMs, there would be more need for Peercoin ATMs than there is right now...
How to break that circular reference?
I'm glad you mentioned NuBits, because I think maybe NuBits is something we can hope for. Here's why: NuBits is meant to be used as transactional currency (in difference to Peercoin). An Android wallet is in development. Paying with that wallet requires NuBits in that wallet. If you need to reload your wallet with NuBits when you're away from home, an ATM supporting NuBits wouldn't be bad.
The current distribution of NuBits includes dividend payment in Peercoins. I expect that to stay for some time, because it's an incentive for NuShares holders to vote for a custodian if they receive Peercoins for granting the custodian with NuBits (to fill the market needs for NuBits). This is how they get rewarded for trusting somebody with a large amount of NuBits.
The more dividends that are paid, the more buy pressure is on the Peercoin market (or the less sell pressure if you consider mining the PPC for the dividends without sellling them at exchanges). Either way, the dividend payment has either no influence on Peercoin price (in case the receivers of dividends sell them after having received them...) of a positive influence.
So NuBits might indeed help Peercoin to get where we expect Peercoin to belong to 
But there's another idea that might help Peercoin.
I think the backbone aspect of Peercoin is something for the future. It first needs to get there. It will get there once people recognize an intermediate use case of Peercoin: to invest now and wait for the price to rise!
Peercoin is the real digital gold (in difference to Bitcoin): once you have made it your own (by purchase or mining), it can be kept for very little effort. You don't need much to maintain its value.
If you get people to realize that, you have created demand for Peercoin ATMs and a lot more...
Trying to find a company that supports Peercoin at their ATMs is a good idea. I only don't know how to convince them of including Peercoin transactions at that ATM... That might require some sponsoring.