Most 76's start at the low E. As Fran said, perfect if you do LH bass.

There's somewhat of a shift towards 73's in many stage keyboards, starting at the low F or even low A (Krome73). But Korg's Kronos 73 starts on the E. Go figure!

This sort of emulates the Rhodes range, though why they messed with the Rhodes's low E beats me. Wurlitzer EP's started on the A, and were 63's.

On the whole, the 76 seems something of a dying format, which I can't fathom to save my life. Why would anyone want LESS than 76? At least Yamaha still do their TOTL WS's in the traditional 61, 76 and 88 ranges, with the 76 starting at low E.