hmm well that's new to me, i didn't know about that, but if the person is doing dust payments then the generating new address method be useful in my opinion. A person gets $5 from a faucet, spends $3 to buy a key etc in that case multiple address will be helpful for him, as the number of inputs will be low as compared to 1 address receiving multiple payments...
No... that's not how it works... Example:
FaucetUser gets the following payments from various faucets to his address 1bitcoinAddr:
0.00010000
0.00015000
0.00012345
0.00022000
0.00020000
So in total they have 0.00079345 btc... and it is all in one address, but it is spread across 5 inputs... now say they want to transfer 0.0005 to someone... most wallets will use something like this:
0.00022000
0.00020000
0.00012345
ie. only using enough Inputs to cover the amount transferred (+ fee)... now lets say they had 5x bitcoin addresses and got those same inputs:
1bitcoinAddr1 - 0.00010000
1bitcoinAddr2 - 0.00015000
1bitcoinAddr3 - 0.00012345
1bitcoinAddr4 - 0.00022000
1bitcoinAddr5 - 0.00020000
If they try to sen 0.005, the wallet will still use 3 inputs to make it up...
1bitcoinAddr3 - 0.00012345
1bitcoinAddr4 - 0.00022000
1bitcoinAddr5 - 0.00020000
So, it doesn't matter if those 5 inputs are all in one address... or spread across multiple addresses... they'll still need to use those 3 inputs to make 0.0005... and the transaction will be the same size.
TLDR; just don't accept small amounts of BTC