Apple are notoriously good at safeguarding user data & safari actually blocks third party cookies. But yeah, it’s a lot of personal data in one device.
The hilarious thing is ad/PR agencies & brands & content owners & lots of diff companies or ppl scrape Twitter for research. Twitter monetise the content she’s wasting her life providing them. Experian (who she’s worked for) sell data to brands to enrich customer data for BI or CRM purposes - so the emails brands send you could very well be considering your household income or if you’re a credit card shopper.
And yet it’s saving 50p off strawberries she’s got beef with?
key stage 2 thinking yet again