nice feature, but is there a reason why we don't use the other parameters of ChatInviteLink here too? Similar to how we do in send/edit_location

TBH, I hadn't really thought about it, but interesting idea! you'd do something like e.g.

if isinstance(invite_link, ChatInviteLink):
    expire_date = expire_date or  invite_link.expire_date

? That could work. If we want to allow users to e.g. delete the expire_data, we'd have to maybe do something like

def edit_chat_link(…, expire_date = DEFAULT_NONE):
    if isinstance(invite_link, ChatInviteLink):
         expire_date = expire_date or invite_link.expire_date
    expire_data = DefaultValue.get_value(expire_date)

such that edit_chat_link(chat_link_instance, expire_date=None) allows to explicitly set expire_date to None.
And we'd have to mind that one could want to override member_limit with creates_join_request and vice versa.

At first glance, I'm not sure if the added convenience is worth the added complexity of the method. What do you think?

ugh, in that case probably best to leave it like this. Not to mention documentation will also increase in complexity.