The entire purpose of joining NATO is to defend against russian imperialism (Something Sweden has a ton experience with, for hundreds of years) Always has been. There is not much point in joining if you exclude that bit.
Certainly the main purpose, but I think over the last 70+ years there are some other benefits to members.
For example, fostering trade of military goods and technologies between members (especially for the USA as a major exporter) and smoothing out their national budgeting since it's kind of like buying insurance.
For example, fostering trade of military goods and technologies between members (especially for the USA as a major exporter) and smoothing out their national budgeting since it's kind of like buying insurance.