The running of a bank doesn't seem like a likely premise for a comic fantasy novel, and even Terry Pratchett doesn't manage to pull it off. Making Money is his weakest novel in years.
The problems start with the leading character. Moist Von Lipwig, a con man who had received a gallows reprieve to take charge of Ankh-Morpork's post office in Going Postal, now gets an offer he can't refuse to run the most important bank in Ankh-Morpork. Colorful rogues are, it's often said, more interesting than honest characters, but this isn't true with Pratchett. His most compelling characters are the ones who are driven by their own standards. Granny Weatherwax, Sam Vimes, Angua, Brutha. Lipwig can bluff his way out of any situation, and losing him wouldn't seem like that big a deal. After all, he's already been hanged once.
His opposition, consisting mostly of the Lavish family which has owned the bank for generations, isn't particularly impressive. Cosmo Lavish schemes to take over Ankh-Morpork, but his obsession with Lord Vetinari undermines all his efforts from the start. He never feels like much of a threat.
In addition, Pratchett shows a really poor grasp of economics. He shows Ankh-Morpork moving from a gold standard to fiat money, but doesn't understand either one. His idea of the gold standard is the Fort Knox model, where the bank keeps gold buried in the ground but doesn't allow its notes to be redeemed; that's just slightly disguised fiat money, and at least he recognizes its phoniness. Moist's great innovation is simply to change what's buried in the ground.
Fiat money does work in its way, aside from its vulnerability to inflation and other manipulations, but it has value because governments accept it in taxes. The value of a dollar bill is really that of a stay-out-of-jail card. Lipwig, being a con man, sees currency as needing to have impressive-looking designs and to create a general impression of trust and nothing more, and nothing ever proves him wrong. I have to suppose Pratchett backs him up on this point.
At one point in the story, a wonderful new (magical) technology comes into the hands of Ankh-Morpork, which would save huge amounts of labor. The local economist explains that it mustn't be used, because it would put thousands of people out of work. If the notion that technology destroys jobs were true, we'd all be starving today, our jobs wiped out by the exponential growth of cheap computing power. Technology frees people's effort for more productive uses. There might have been an opportunity for a more subtle point, since the change would have been sudden and the transition painful even for as enterprising a city as Ankh-Morpork, but that's not what Pratchett had his economist say.
There are still quite a few good points to the book; even a bad Pratchett novel is better than most of the competition. Lord Vetinari is at his most manipulative. The plot is twisty and full of surprises. The bank's head clerk, Bent, is intriguing. In spite of his name, Bent is as straight as an arrow and has an astonishing head for figures, but his past contains a weird secret which he considers shameful. He provides a complete contrast to Lipwig while having to work closely with him.
I'd suggest waiting for the paperback.