Great location, minutes away from the Giardini and the venues for the Biennale, and also convenient for vaparetto stops. Also, next-door Via Garibaldi has supermarkets (not always easy to find in Venice) and other useful shops and cafes. The flat itself is, as indicated, small and rather dark, but very clean and with a good bathroom. It is also a little damp - but this is of course a hazard in ground floor flats in Venice, and it was certainly manageable. One thing to note is that the flat was pretty bare of essentials - no soap, dish soap, hardly any toilet paper, etc. for a short stay it was a little inconvenient to have to buy such things.
All in all, given prices in Venice, the apartment is fairly priced and very suitable for a short stay where you'll be out and about during the day.