That's a fair point and in the short term, I'd tend to agree with you.
But I think you have to consider where this may lead. In the start it could be little to worry about for law abiding citizens but there's a huge possibility - inevitability perhaps - for scope creep. Each incremental erosion of privacy may be sold as being necessary for reason x or y, innocuous enough at the time. But gradually, freedoms will be eroded further and further.
Anyone who thinks this has anything whatsoever to do with stopping illegal immigration is kidding themselves. This is about government control. A socialist big government wanting as much control over its citizens as it can get. Tracking what you do, where you go, who you meet, what you post, what you eat, how much you drink. No more anonymous posts on social media, no more criticism of government policies.
Look at Mahmood latest proposals to inhibit repeat protests. Overtly about Palestine Action. In reality it's about stopping protests outside asylum seekers' hotels.