> a device that holds your entire life, bank info, photos, etc
That device was called personal computer for decades, and the world didn't end for the simplicity of installing software on it.
The world may not of ended but to of people have been hurt by malware ruining their computer, cryptolocking all of their company's files for ransom, stealing all of your login credentials, stealing cryptocurrency, taking secret photos with your webcam, screen recording what you are doing on your computer, etc.
The "personal computer" has a terrible track record.
> That device was called personal computer
To be fair, mobile phones being locked down probably contributed to the mass adoption of e.g. mobile payments and banking.