Support for lad-hebr on Ladino Wikipedia

I'm just curious that why we can't have a Latin-Hebrew converter for Ladino.

It's possible, but not easy. There are several orthographies for Ladino in Latin script, and any converter would have to be able to detect which orthography is being used. (Alternatively, I suppose, any page in lad-latn would have to identify its orthographic system.)

The opposite is much more difficult. The mapping from any given Latin orthography to Hebrew is essentially one-to-one, with the caveat that initial vowels need special handling, and so do certain final consonants. But the mapping from Hebrew orthography even to a single, preferred Latin orthography is not. For example, the same Hebrew-script vowel is used for both i and e, and a different Hebrew-script vowel is used for both o and u.