To be honest, isn't 25 years too much? He didn't beat or kill anyone, he simply found dumb people and took little of their money. It is not like he was robbing poor people by increasing their utilities bill every year or raising rent. Why is such a small, non-violent crime so severely punished? Of course he deserves a punishment but maybe not that much?
As the article says, it sends important message. And he does not serve 25 years.
I don't know how it is the US, but in Finland people get relatively longer sentences for financial crimes because long sentences have inhibitory effect for money crimes.
Most violent crimes happen without premeditation by people without impulse control and longer sentences don't actually reduce crime. White collar criminals weigh the costs and benefits and do their crimes in cold blood after long time of planning.
If you make a scammy-looking cryptoexchange and promise I will get rich if I invest, you won't be able to steal a single cent. Only dumb people can believe that you can buy cryptocurrency and get rich without doing nothing.
But poor people suffer much more from raised rent than rich people from losing little money on dubious cryptocurrency investments. If the punishment was based not on absolute dollar amount but on damage relative to person's total amount of money then it would be more fair.