I agree basically, but just for information to everyone I will mention that there are some studies that indicate plants will use nitrite, but only if ammonia/ammonium is insufficient. Most aquatic plants prefer ammonium (ammonia) and they use it for two purposes, to synthesize proteins and (primarily) to store as ammonium for their nitrogen source. Apparently, according to one study (which Diana Walstad references in her book Ecology of the Planted Aquarium) aquatic plants may turn to nitrite if ammonium is insufficient, but not directly because taking up nitrite means they have to convert it back into ammonium. Same holds for nitrate, it too is extra energy to change it back into ammonium so the second choice, so to speak.A tiny correction - plants use ammonia, and nitrate if there is no ammonia present. They don't take up nitrite at all.
Walstad cites one study where a duckweed species Spirodela oligorrhiza was grown in a medium containing both nitrite and nitrate, and the duckweed clearly took up nitrite in preference over nitrate. But as Walstad mentions, aside fro this study there is [at the time of her writing] no clear data that plants generally take up nitrite over nitrate when ammonium is insufficient.
The uptake of nitrite is not something we should rely on as it will almost never be significant compared to the Nitrospira bacteria. Plant fertilizers for aquarium use generally provide nitrogen as ammonium and/or nitrate. Plants will in most situations take up all available ammonium (there is obviously a limit but hopefully no one would ever have that much ammonia/ammonium in a tank with fish) so the uptake of nitrite/nitrate is going to be minimal. There are a few species that do seem to prefer nitrate, but I needn't get into that.