When a customer purchases or does anything with bitcoins, he/she would have a track of it. All transactions can be monitored at any point. It helps save more money as well. No third party's involvement. If more bitcoins are used, then many merchants would start accepting it. Its very comfortable for them as they no need to go to bank for any other transaction they make. There are many other good reasons why customers use bitcoins.
That is the benefit but there is no assurance also that you can monitor or trace the real identity of the transacting party, other payment processor require their clients to fill up all the required information as they are also required to comply with the KYC policy to avoid money laundering.
The problem is even if you know the address you are sending is you can't really associate it with him/her not unless they officially stated that they owned it. It can lead to a lot of confusion when that happened also making it hard for the transparency to happen. Suppose that a coffee shop accepts Bitcoin and all of the customers pay using bitcoin. The shop won't receive it instantly and it will be waiting for confirmation on all of them so that the tracking of all who paid is actually harder than you thought it would be.