Crank power meter incompatible with my bottom bracket
There’s no kind of adapter to fit the power meter crank to a square taper spindle, it seems to be a Hollowtech II left crank power meter (Shimano 105?). You’d need a crankset with the same Hollowtech II interface. You’ll need to check the width of the Bottom Bracket (B.B.) shell on the bike frame to see if a road crankset will fit. 

Also note the gearing may change, with a road crankset, I think the spec says it’s a nine speed triple which you would want to match the best you can, probably Shimano Sora IF you have a road B.B. shell (68mm). 

If you want to replace the crankset you’ll need to swap the bottom bracket too, which is no great obstacle, but might require tools you don’t have. Will also depend on the B.B. shell width. 

Economics are up to you, you can add up the cost of the new crankset and bottom bracket plus tools or labour, and compare that to the cost of selling it and buying pedals. 

I can foresee a case for the pedals, certainly it could be mechanically simpler to install pedals. You’ll have to see if it’s cheaper where in the world you live