The bucket does literally the same as if you just do "/giveme mcl_portals:portal_end". It just places a single end portal node. Apart from the new texture, there is no innovation. It is now easy to add "invalid" end portals everywhere but it is not trivially possible to remove them.
If it just places a single end portal node, I suggest as an improvement that collecting the portal sucks up the entire portal, and placing it hollows out a depression for the portal, and places the entire portal.