Incorporating Strava into CJ training plan

I’m being gifted a Strava annual subscription but I don’t know how to incorporate or use it alongside my CJ training plan. Having browsed their website, it seems that the training plans (which are 4-5 weeks in duration) are geared towards improving one’s performance in relation to segments, and I don’t know whether those would translate into an improvement in a marathon race situation (I’m a mountain biker). To be honest, I’m not sure what the purpose of strava is as a training tool, so I would welcome suggestions.