Treasury notes are safe in that you are likely to get the dollar amount back. However, inflation will take away the purchasing power of those dollars over time. Compound inflation is like compound interest-over time it mounts up.
For example, $7,000 USD in 1915 would equal the purchasing power of $146,000 today.
Inflating is a hidden tax on those who save.
Do we have a disincentive society? Corporations are taxed, capital gains are taxed, interest is taxed and dividends are taxed. On the other hand, sometimes it seems that that the idle and the improvident are rewarded-like right now. And that the criminal are rewarded by benefits-illegal immigrants, for example.