The argument is more, Google will try this data to its advantage. This may be convenient for you or even sometimes a real advantage, but there will also be situ

The argument is more, Google will try this data to its advantage. This may be convenient for you or even sometimes a real advantage, but there will also be situations where they use it in a way which is advantageous for them and a disadvantage for you. Let's make up an example. Google scans emails with your purchases and their frequency and accumulates a pretty good understanding of your purchasing power and income situation. This can, for example, be used to sell advertising space for ads which are geared towards a specific income strata. So far so good. But the data is also in principle open to companies like credit reporting companies. But let's drive it further, your landlord might be interested in the data because it tells him precisely how much he can increase the rent before you move out and rent something cheaper. A counter-argument which I see often is that companies like Google and FB do not sell personalized data abut people because data is in some way capital for them. But cases like Cambridge Analytica show quite clearly that FB was already exchanging personalized information against data. It is only slightly simplified to say that they are already selling data.