system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it that so many random sites have their own app and care so much about getting me to use it over just viewing the mobile version of their site?
gpt
Their app allows a level of surveillance and interaction that can't be achieved via a mobile website.  It also 'ties' you more closely to the site so you're less likely to move on to other, similar sites.