Is TRX the same as USDT?

Could you clarify for me if TRX and USDT are interchangeable or if they serve distinct purposes within the cryptocurrency ecosystem? TRX, being the native token of the Tron network, and USDT, a stablecoin tied to the value of the US dollar, seem to have different functionalities and use cases. Are they essentially the same, or do they fulfill separate roles in crypto transactions and investments?