On most websites, you download more ads and trackers than actual content. By blocking them, you will save your precious mobile data.
Your Internet Service Provider can see what websites you visit on your iPhone, and how often. This data is stored for long periods of time, and made available to law enforcement, advertisers, and data brokers. There is no reason for them to know what you do online, especially while on the toilet asking the real questions.
When you browse, your iPhone connects to thousands of web servers every single day. Most of these connections are to advertising and tracking services. By eliminating these pointless connections you will notice a huge improvement in page load times.
If you download shady software or open email attachments from people you don’t expect to send you attachments, a VPN will not help you to stay secure. Basic common sense and operational security always comes first, which is free.
iOS devices are basically spy tools full of cameras, microphones, and sensors that track your every movement. Simply changing your IP doesn't magically make you anonymous. Windscribe will help you reduce your data leakages, but the rest is up to you.
VPNs are not at all helpful in getting you matches on dating apps. Not really applicable, but worth a mention.