CCleaner is good enough, unlike the other cleaners that also include junkware/bloatware of features that not many people use, CCleaner does not, it just gives you a nice cleaner, stable and good interface.
From what I can see on Baidu's website it has a lot of other features, some I might even consider a vulnerability, eg wifi hotspot. Turning your computer into a wifi hotspot not only compromises your security if not properly configured, it also encourages attackers because you are basically holding out bait and saying "please try".
Also like the others have said, how much do you trust Baidu to be in your computer, clean up, optimize and make your PC somewhat smoother for absolutely $0. The only way they are earning from this is ads and selling data to other third parties, and for Baidu their third parties are not very broad in range because they are based in China. Another thing I would like to point out on why I don't like Baidu was because of the recent incident where their search engine was the cause of a very large DDoS on Github, according to them they were unaware of it happening however it took them wayyyyy too long to solve the problem for such a big company. If the DDoS was directed at the Chinese government I'm absolutely sure that the DDoS issue would have been solved in a day if not less.