Also the example of bypassing this is rather contrived:

1) bypassing some timer in an API service requires the API to accept the string „Infinity“ and convert it to the JavaScript value Infinity - which is highly unlikely. Instead, the value would just fail the numeric validation.

2) bypassing some timer in client-side code by injecting Infinity seems overly complex - if you alter client-side code you might aswell just remove the validation instead of abusing edge cases of the language runtime.