Yes, not all demand is the same, but the idea isn't to increase the demand of bread, it's to increase investment. If sitting on cash gets you more interest from the bank you're going to let it sit more. If it loses value you're going to spend or invest it more. And yeah, this does happen, among other things because inflation affects everybody, not just consumers, although this also influences how likely individual people are to buy things on credit. Companies and governments also care about this.

As always with economics things aren't straightforward, and you get lots of weird paradoxical behaviors, but the big lines of this one are easy to see. If you have some inflation and low interest rates you're gonna be more likely to make big purchases or investments on credit. And the real problem is once you have those and are paying them back if inflation flips and suddenly the 100 bucks you pay each month for that credit go up in value to 110 you may find yourself losing money on that investment or being unable to afford it, which is a big problem when that happens to literally everybody who owes money (including the government) all at once.

And since the people you owe money to are mostly just a handful of banks.... well, that's not a great wealth redistribution technique, is it?