The hashtags in the changeset comments are not a specific Nepal problem.
For many years mappers used the comments according to these ideas:
„There are many reasons why you should make use of the changeset comment to describe your edit:
• Out of courtesy to your fellow mappers, since it makes it easier for them to understand what you have done and why. Not using a changeset comment has the air of “it’s none of your business what I did here and why” and doesn’t fit well with a project where we’re all working on the same thing!
• To avoid misunderstandings and get mistakes fixed quickly – if an edit with a changeset comment of “traced a couple houses from Bing” deletes 50 restaurants then it is immediately clear that this must have been a mistake, whereas a changeset comment of “removing restaurants which I found to have closed during last week’s survey” makes it clear that you really meant to delete these restaurants for a good reason.
• To increase the value of your edit and prevent edit wars by explaining why you did something and what your sources were. If someone finds you have added a house that is not visible on their aerial image they might be tempted to delete it, but if your changeset comment says “added newly erected building” then they will think twice!
• As an aide memoire. Changeset comments help you to remember what you did, and why and when. Remember that it may be in 6 months or 1 years time ahead that you want the information in the comments, and it’s difficult to predict why you need to find an old edit. In short: Eat your own dogfood!“
All these hashtags in the changeset comments contradict to these ideas!
The wiki says :
„Some users have begun using “hashtags” within changeset comments. As hashtags are usually aimed at machines, not humans, there has been some debate about whether hashtags belong in “good changeset comments”, and it is not widely agreed. OpenStreetMap allows adding other tags to changesets, and machine-readable keywords would have a better home in a separate tag like “keywords” or “hashtags”. As of August 2017, the iD editor supports a separate “hashtags” field with changeset uploads. Despite this, some tools will pre-populate the changeset comments with hashtags, meanwhile other tools will use, or even depend on them for analysing/visualising changesets. Hashtags are simply words within the free-form text field with hash (#) prefix. They can be used alongside, or interspersed within, text composed manually as a human-readable comment, and certainly a good changeset comment should do this rather than only including pre-populated text.“
I think the use of hashtags has been greatly promoted by the HOTOSM tasks.
There task-specific hashtags have been inserted automatically since years and so unexperienced mappers might have considered this as standard.
This has, as far I understand, also some commercial aspects. KLL id doing some paid mapping and therefore they “mark” own managed mapping using the hashtags to show it to the institutions they pay for that (e.g. World Bank).