Yes, I Bonds are a good alternative to CDs. But it's important to remember that the 6.73% is only for the next 6-months. The 6-months after that will depend on the new rates issued next May. If inflation comes back down to a reasonable level, the I Bonds rate may be much lower.
Here's the link to the Treasury I Bond page:
https://www.treasurydirect.gov/indiv...res_ibonds.htm