The site cryptowat.ch does this and I love it. I feel it helps to see where in the dips and climbs you got in or got out. In their implementation you only get to see a chart by coin by exchange (which makes sense because they show it down to the minute). But with CoinTracker I think it would be great to be able to see all the transactions of the same asset plotted on the same price chart, especially since you already list them all together as transactions below.
For example, if I bought/sold Polkadot on three different exchanges during the same month, it would be great to see those transaction points all show up on the same aggregated price chart for Polkadot.
Attached is a screenshot from Cryptowat.ch and rough mock-up of it could look like on CoinTracker