N2O has been worked with very early on in the 40s and now again is seeing a resurgence. Is this interest merited, disregarding its apparent non-toxicity, and how well does it perform in an engine/general handling characteristics? This question is not concerned with the characteristics of mixed monopropellants of N2O nor with bipropellant systems.
According to Science Direct:
Nitrous oxide (N2O) is considered a potential monopropellant for micro-thrusters applied in micro-spacecrafts as a result of its special properties, such as non-toxicity, self-pressurization, and self-sustaining reaction.
So, I would think yes if it is considered, but there are better options, such as, according to Wikipedia:
The most commonly used monopropellant is hydrazine (N2H4), a chemical which is a strong reducing agent.
This is most likely because it is more practical for some reason or another. The primary difficult with nitrous oxide however, making it very hard to use, if not impractical is stated by a a Harvard sub-site:
It has been largely overlooked due to the difficulty involved in maintaining reproducible catalytic decomposition
According all the referenced sites above, people are attempting to make N2O monoproellants that fix the from I just said. So, it is not practical currently, but may be in the future.