I received a GitHub issue about this a few days ago, so I will post what I said on that thread here as well:
min properties are passed to the underlying native
input and as such as subject to the behavior that has been implemented by browser vendors.
If the value exceeds the
max or is less than the
min, then the input fails constraint validation. In other words, users can still enter any number they want, but if the number is out of the accepted range then the form will not submit.
You can see the same behavior using a native
input outside of Ionic Framework: https://codepen.io/liamdebeasi/pen/rNjQEYK
pattern property. Please note that if you use
pattern then you will need to change the input type to
text: HTML attribute: pattern - HTML: HyperText Markup Language | MDN