You should view her as an American hero and this is one way to honor our heroes. What I find in poor taste is that we haven't honored her in some equivalent fashion until now. The Tubman museum in Georgia is pretty great though. There's a statue in Maryland too. Outside of that, on a national level, I'm not sure what we've done.
I liked it when Liberty herself was featured on the coinage. I'd vastly prefer it if the currency denominations featured various depictions of Industry, Agriculture, Liberty, Justice, and Science/Truth rather than politicians and/or revised and sanitized historic figures. The other side can feature economically significant animals.
Besides that, the money portraits seem a lot like icons of the Americanist pseudoreligion (as satirized to great effect in Bioshock Infinite), and a betrayal of the idea that the US is a nation of laws, not men.
For instance, a Saturn V rocket is a suitable subject for a money engraving. A portrait of Neil Armstrong is not. A Model T is an acceptable subject. Henry Ford is not. A Texas oilfield is suitable. John D. Rockefeller is not. A railway locomotive is okay. Cornelius Vanderbilt is not. The light bulb is acceptable; Thomas Edison is not. A harvester in a productive wheat field is acceptable. The politician that penned the farm bill is not. Blindfolded Justice, with scales in one hand, and sword and laurels in the other, would be great. John Jay would not be.
Real people all come with baggage. Ideals are clean.
I'd also love to see Chicago Pile-1 (first supercritical fission reactor) at Stagg Field on money.
Shopkeeper: I'm sorry, I can't accept this bill as legal tender. It doesn't say that it's not legal tender—ergo it is legal tender, ergo it's not legal tender.
I understand on "the Native American problem" he was faced with an untenable status quo and even worse ideas from the states in question. However, solving it by negotiating with largely unrecognized leaders, then forcibly relocating ethnic populations across the country in exchange for dubious reimbursement for their native and sovereign land doesn't exactly seem a moral solution.
It certainly could have gone worse had the states had their ways, but his solution wasn't exactly a paragon of ethical behavior.
So she's a former slave, a liberator of slaves, and a plantation owner and owner of slaves all in one. Would having her on a bill be in poor taste? (Granted, there are probably more prominent persons who should be on a bill before her.)
(I once dated one of her descendants.)
And anyway after the 30 picoseconds of novelty the people will only look at the numerical value and just ignore that there is a human there. And by the time it enters circulation we will be in cashless dystopia.