It's kind of a neat idea.
The way the coin works, only a certain amount is tradeable, whatever is mined ... All else is locked up and cannot be traded. As far as I understand it even the developer can only trade the amount he mined.
Current tradable supply is only a little over 9000. If my observations are correct this could mean a greatly increased price in the future as there is not many available for the time being.
Then again, who's to say the website will still be around in 50+ years?
Now I could be understanding this wrong and if so do let me know.
Your understanding about minerum is correct and about the price, It could pump higher due to limited supply it emits everyday. But the only use case of MNEB is to pay for services in the minereum website like coin creation and staking other than that its almost the same as other tokens, A tool for speculations.