If you have the money to burn then why not? buy it now? other than that, if you're happy with your setup, why bother upgrading to something just because it's on special?
I bought my plex pass when it was $75, for the age restriction function and multi-user as I have a small child. He can have his own user and I can restrict his user to be only able to watch things below a certain age restriction or just all ages stuff.
And to use the Plex kodi addon, when I bought, It was restricted to paid users only (Not sure if that still the case ) - I am not huge fan of the Andriod app. The Kodi addon worked better for me.