Devanagari numerals (१, २,...९) are default when you select Hindi irrespective of different options (BolNagri, phonetic, inscript, etc). In reality, Indo-Arabic numerals (0, 1, 2,...9) are used in Hindi newspapers, magazines, text books, government publications, etc. It really get on nerves if you want to write something in Hindi on Wikipedia because you have to switch over settings so many times. So it would be really helpful if developers could provide options for selecting numeral system also. Regards.
Topic on Talk:Universal Language Selector
Well it is for Hindi Wikipedians to discuss but with simple Control+M you can toggle (shift) between the scripts Roman and Devnagari. I do not think you need to switch over settings so many times. I tested १1२2३3४4 for Hindi लिप्यंतरण option just now. with ease I did १Control+M1२Control+M2३Control+M3४Control+M4 १1२2३3४4 it did not take many seconds. In any case you use shift button for some letters simillerly you are using Control+M instead so it does not increase many strokes. Seondly if you have an entire different keyboard for roman numeral+ hindi alphabates to type १1२2३3४4 this you will end up switching key boards. So rather using Control+M seems more logical to me still it is for majority of hindi wikipedians to decide and request the changes. Still I suggest a revisit to your request