Presenting twice at same conference I applied to a pretty broadly-themed conference in my research areas, and submited two very different contributed talk abstracts. I suspected one would be downgraded to a poster, or simply rejected. Instead, the organisers told me I could present both talks. Looking in the abstract book, I see that no one else will be giving two talks. Is giving two talks in poor taste?

Specific background: I am an early postdoc, and the conference is in Europe. Both research projects are new and have not been presented elsewhere, and are with completely separate sets of coauthors.
It's totally fine.  I commend your efficiency.

It would not be fine if you submitted two similar talks, or if you submitted a talk under someone else's name so that you could pretend to fill in for them.