Hello,
In my experience, whether your boosted proposal will work or not really depends on the job poster / client. Sometimes I boost my proposal and still my proposal does not even get read. Other times, it gets read but still does not mean I will get invited for an interview.
However, I think that in the long run, your chances of winning jobs with boosts is better because most job posters are lazy scan all the proposals, let alone read them. They likely only take a look at best matches, they also invite some people and MAYBE take a look at a few other proposals. Most of my proposals in my brief experience as a freelancer do not even get read despite the fact that I have a strong background. It all boils down to how Upwork's algorithm really works.
