I am not even sure if the coinmarketcap application is legit because if there was an application most traders would be able to know and talk about them but as far as my friends know, they mostly use blockfolio for the list of their coins and tokens they have on hold. And same as mine, I only use the blockfolio app because it is updated and I a, comfortable using them as well.
Like you I didn't know that app of coinmarketcap, all I know is their main site. I'm now using delta app I downloaded it recently and it's great to use yet I'm not sure if it's now available in app store but in playstore it's perfectly working.