We had a discussion about this one not too long ago.

https://news.ycombinator.com/item?id=45887957

Unfortunately, with the mobile OS's datepickers being so bad from a usability perspective, it's a long way from being a solved problem. Typing the date directly into a single textbox is great for some of us but not for others, so an alternative has to be provided.

Yes, some date selection widgets can be poorly designed and user hostile, but the well-designed ones tend to be fine. The ideal, based on real user research by gov.uk, appears to be to use 3 separate textboxes, instead of <input type="date">.