Before listing the arguments, lets first clarify what a scam is. According to the Cambridge Dictionary a scam is a dishonest or illegal plan or activity, esp. one for making money - the following list of facts will prove this. (BitCoin=BTC, BitConnect=BCC)

i: Terms of Service

The good old ToS we just agree to without reading it. According to BCC's ToS, section Material risks related to BTC: (...) The volatility and unpredictability of the price of virtual [BitCoin] currency relative to the fiat currency may result in significant loss over a short periods of time. Any technological difficulties experienced by the Bitconnect system may prevent the access or use of members virtual currency temporarily or permanently, depending on the severity of damage.

What does this mean senpai?!?! This means if the price of BTC drops significantly BCC may block access to the wallets of fear that people might cash out since BCC is based on BTC. Here are some of the drops with minus 80+% we had with BTC over the last years.

ii: centralized market, centralized power, centralized danger

This is a follow up based on the point above. Over the last 24 hours a volume of 30 million dollars has been created, %96 of that on BCC's own website.

This is a huge problem, not only do founders of BCC have the control of the majority of the network but also pose a great danger as we saw a couple of days ago when a person or a group of people used an exploit of the website and sold a massive amount of tokens, making millions of dollars, letting the price drop by some %65+ and ending up preventing access to the website and with that the market.

It's not about that such a thing might happen, it did happen and some people out there made a lot of money with it.

iii: being carried by someone else's success

What does BCC bring to the table what BTC's doesn't have already? BTC did recover over the past years from the massive drops like we had in 2011 or 2013 but how should BCC be able keeps its promise during such a recession? Especially if the outcome of a lending is in USD/EURO and not BCC.

iv: transperancy

Source codes and detailed analysis of inventions are a significant for the future of a cryptocurrency. We know how several networks function, when it comes to BCC: do we know how the price volatility software, trading bot functions? If there is a guarantee to profit from BCC investment how can a software make profits when BTC and with that BCC will lose value over a longer period of time?

iv: referral spam, guarantee to become rich as fuck etc etc

This. Just don't, just don't.

This is just a short breakdown, which should show you that with BCC being based on BTC, a longer term downfall of BTC will create enough drama and callouts to show the weakness of BCC only in one of a long lists of topics.