I wouldn't say that Chelsea winning the conference cup is a big milestone achieved, because they're bigger than that competition and the competition is filled with third class clubs. However, I applaud them for winning the CWC tournament and that's is a great achievement for them. I hope to see Chelsea put in this superb performance in EPL and UCL next season.
I would say differently and I would consider it as a milestone for Chelsea. It's never easy to win Champions League, Europa League or Conference League by their cup formats. You can be a strong team but in cup, if you lose only one match, you can lose the trophy and it's really different than in domestic league with a champion decided by total collective points in a whole season.
In addition, Chelsea won Conference League and made their name as a first ever club that take all three trophies: Champions League, Europa League, and Conference League. It's truly a milestone for their club history.
But at least Chelsea have done their best and Enzo Maresca who was considered to be lacking in ability, has proven to be a significant improvement for this team. We'll see how Chelsea performs next season, whether they will be a title contender or struggle to keep up with the other teams.
They began to rally with Pochettino who left the club two summers ago, and Maresca did continued the club development well since the last summer. They are working hard together and are improving themselves over time. This Chelsea under Maresca management can potentially become a very strong team in next one to three seasons. They will be able to compete for Premier League and Champions League titles if their growth continues smoothly.