[another-cuppa]

Remember Atlassian in their infinite wisdom renamed the on-premises product formerly known as Stash to Bitbucket despite being a completely different code base to Bitbucket.com. I think they are talking about Bitbucket.com.

[leoedin]

The bitbucket.com website gives a check box to select whether to close a branch though. Unless you mean that the on-premises product doesn't?

[another-cuppa]

The on-prem one I use has checkbox when you merge. It's unticked by default.

[gpm]

The on prem version I was using a month ago had a checkbox, ticked the last way you checked it by default.

So if you merged feature -> develop -> master and remembered to delete feature it would delete develop by default as well...