No one can say Chelsea is a weak team. Chelsea is always a big and strong team although they are difficult playing at their best form lately.
Sure, Chelsea won't reach the current stage/round if they are a weak team. Don't forget that Chelsea is the leader of group E on the group stage. It proves that Chelsea is a strong team.
However, if we compare the squad quality and coach quality, Real Madrid is still better than Chelsea. Real Madrid also has a better experience and achievements in UCL. I never underestimate Chelsea squad, but I'm sure that Real Madrid will have a bigger chance to qualify for the next round. I even predict that Real Madrid will play in the final round.
these are two different facts for Chelsea this season because Chelsea performed quite well in the Champions league but in the Epl they were unable to compete at the top of the standings because of the defeat after defeat they received. Chelsea will face Real Madrid in the quarter-finals. Now, this is where we will see Chelsea strength. We will see how strong they are this season after the opponent that was met in the draw was Real Madrid.
I also agree with your point where the Real Madrid vs Chelsea match is more likely that Real Madrid will come out victorious and qualify for the semifinals. The depth of Real Madrid squad is better than Chelsea this season and even Benzema quality cannot be doubted as a really good sticker on Real Madrid front lines.