WhatsApp's latest update improves contact details attachments by letting users send the contact details of multiple contacts in a single action. More specifically, if you need to send someone the details of multiple contacts at once, for example, the numbers for your co-workers to a new employee, then you'll now be able to do so once you have the newest version of WhatsApp installed on your device, though it should be noted that this may just be for users who are on the most recent beta, which you'll need to be a beta member to have access to. For avid WhatsApp uses this is a nice improvement even if it's only a minor one as it makes sending the contact information to people a whole lot easier and it saves time.
Prior to this update you could only send the contact details of one user at a time which made it incredibly tedious if you had to send the information for more than a few contacts. Sending a couple contacts one at a time likely wasn't so bad for most users, but having to send three or more contacts one at a time is certainly more time consuming than most users probably wish to dedicate to something that could be such a simple task. The good thing is that WhatsApp has seen fit to alter this particular function within the app and make things much more convenient for their users.
Right now since this is likely a feature that's part of the beta and not the regular version of the app, it might be a little while before WhatsApp actually incorporates this option into the standard, non-beta version, but it's also been reported that it could have been added in a couple of beta versions before now, which means that if that is the case WhatsApp could end up adding it into the standard app pretty soon. This latest feature follows an earlier beta build from the beginning of March which moved the attachment button to a new location, and an even more recent build of the standard app that re-introduced the text-based status messages.