Yes, I do believe on USD Tether since it's remain stable since a long time ago until now, even there's so many rumors and negative thougths about it, but as we can see even with all of that USDT are remain stable. But I also more believe to my own local stable currency, since I don't need to convert and calculate based on USD anymore.
What you mean by stable since a long time? You mean it is stable among haters' criticism and rumors or sustaining among them?
It is stable in value because it is designed to be so (it may hardly fluctuate +/- 3% of 1 USD and nothing more and nothing less to that). It is existing with us because of the innovation it has brought into the crypto space.
Still, why people do ask about trusting USDT? Because, it is not a mineable cryptocurrency like most other altcoins but is in different format and being controlled by a corporate. So, it may get seized by government if they suspect money laundering for terrorism is happening through USDT whereas if it is a truly decentralized coin then it kind of problem could have been eliminated by characteristics itself.