If it is a requirement that the user must be able to clear the data for each cell in a column, then this practice works just fine. Some suggestions:
- Can you possibly only show the clear button upon hover? Whether this be when the row is hovered over and the corresponding clear button appears, or the cell is hovered over etc.
- Can you change the icon? A simple "X" (cross) button with a simple explanatory tooltip will work well - the current icon is a little misleading as it appears to be a backspace icon, suggesting that by clicking the button individual characters will be deleted. However, if your plan is to have the button clear the entire cell, the icon is misleading and quite distracting.
Overall, I don't see any problem with your current ideas apart from the fact that the icon will look distracting if repeated down the entire column, so have a look into only showing it on hover or similar. Many UI examples only show clear entry buttons upon hover or when the textbox (in this case, cell) is selected.
Hope I helped.