I personally use a spreadsheet and track it the primitive way.
No there isnt. It is not like you are placing in your private key in the app
But instead you just place your # of coins in the app and when you load the app it calculates current price with how many you own (by the # you inserted)
Yeah but you are still sharing the amount of coins you own.
If you're the developers of Blockfolio, you can get a decent overview of altcoin markets this way or worse..
That's true, but they can also check richlist to get an overview about the distribution and the whales in the waters