There is another solution to this: you can use geometry generator to style your pointlayer. As geometrytype, choose polygon and than define an expression like this one:
buffer($geometry, "your_field" )
The advantage: you can play around with the parameters of the expression and observe changes in realtime (like increasing the buffer size by a multiplication factor to get ideal size).
If you want to make your buffer permanent as a separate layer, you can use the "geometry by expression" algorithm from the processing toolbox:
See the screenshot, where I used the fid to scale the buffer - this does not really make sense, it's just for demonstration purpose. Instead of fid insert the name of the attribute field you want to use (in the expression editor under fields and values in the column in the middle). I added a multiply-factor of 500 - otherwise the buffer would have been to small to be seen.