Because of bitcoin does not give public details of people who make transaction with it, some people do say it promote crime. People needs to understand one of the features of bitcoin is freedom that anybody can get access to it, it does not discriminate. The privacy features of bitcoin is very important to humanity, which I know one of its advantage is for safety by using cryptography that makes all transactions safe and encrypted.
I think that the first place where people get it wrong particularly those who have not carried out their research is that since bitcoin is almost associated with being anonymous it therefore means that its transactions cannot be traced. Wrong. The reality is that blockchain operates as a public ledger where if there bitcoin is used for say, laundering, this crime can be traced with a "simple" forensic analysis of the block chain. From Chainalysis report, crimes carried out with bitcoin is not even up to 1%. Criminals still prefer the US dollar over bitcoin.
Transactions involving illicit addresses represented just 0.15% of cryptocurrency transaction volume in 2021 despite the raw value of illicit transaction volume reaching its highest level ever. As always, we have to caveat this figure and say that it is likely to rise as Chainalysis identifies more addresses associated with illicit activity and incorporates their transaction activity into our historical volumes. For instance, we found in our last Crypto Crime Report that 0.34% of 2020’s cryptocurrency transaction volume was associated with illicit activity — we’ve now raised that figure to 0.62%.
https://blog.chainalysis.com/reports/2022-crypto-crime-report-introduction/