How do you know that they could easily afford to pay off all the lenders immediately? They are not transparent with this kind of information. Only way you could know that they can afford to pay off all the lenders is if you blindly trust them without them providing any evidence, knowledge or information. Being positive is generally great, but being too positive is ignorance and ignorance is evil, the only good is knowledge.
Its basic math really, if i bought 10010$ worth of Bitconnect in may, i would have gotten 1250 ish coins for 8$ each, staking these coins would have provided me with an additional 300-400 coins, my total amount of coins + extra minted coins would be worth a total value of 214.000$ dollar if i sold them now 120 days later.
Now if i lended it into the Bitconnect platform for 120 days like most did, bitconnect pays back the principal amount of 10000 + around 18.000 in acrued profit from lending it to bitconnect, so after 4 months i get back 28.000$, bitconnect who has been staking "your" coins all this time makes 186.500$ as they only need to return 215 out 1250 invested coins back to you at the current value of 130$ per coin.
Also, if they keep the other 1035 coins as their reserve, these coins also mint an additional 82.8 coins per minting period, again 10.764$ in the pocket of Bitconnect and this process keeps going as the coin rises in price they need to give back less and less of it, so they acrue most of the minted stakes themselves, causing a snowball effect.
For bigger invested amounts the math stays the same, they just made more money and we people are happy with 1% per day without the risk of the coin collapsing, in this instance Bitconnect is the bag holder, it just turns out to be making profit holding them and they make money of people trading on their site aswell. (Which translates to roughly 530.000$ monthly aswell)
I personally dont know if they have a bot, but they could just run a half assed Gunbot at this point in time, they have the funds to play with and a Gunbot isnt really rocket science either, now compare this system they have in place vs a bitcoin doubler site, bitcoin goes in, more bitcoin comes out is completely diffrent, that why i personally won,t go near sites like thunderbit, Ambis, Control Finance etc on those sites, there is no basic math that you can do to them to see if they are making any money, they just have a "bot" and that supposedly pays out 10% profit a day.