most recent 13week US-T auction that happened on 31 Oct is 4.07% right? (though we can only buy through secondary market hence yield would be diff, but that's besides the point)
https://www.treasurydirect.gov/instit/annceresult/press/preanre/2022/R_20221031_2.pdf
also more recent T-Bills would have higher rate and there's one more 13 week that's happening soon.
anyway the point is not saying 1 is better than the other.
just saying don't dismiss US-T entirely. need to take a more holistic view.
1) if you already have USD in IBKR, then might just make sense to put in US-T even though slightly lower yield cause there might be cost (depending on our banking status) to transfer USD from IBKR to DBS.
2) i believe DBS USD FD has a higher minimum than US-T? that's also another consideration
3) yes as much as DBS has low probability of default, but they are still of higher probability than the US government
4) if your USD is with DBS rather than IBKR, then make sense to do DBS.
the point i am trying to make is, when i post a message I don't know the individual circumstances of everyone, but the logic should apply to all, and then depending on individual circumstances it may or may not be suitable for your circumstances.