Interesting to see a thread like this.
If you are really interested in Bitcoin, I benefited greatly from this free video training:
http://bitcoin.cbtnuggets.com/
The business there is actually a good training company for IT people (or at least was when I used some of their vids). I'm also assuming those are the same videos they put out which I saw years ago now. Some of the people there were quite excited about Bitcoin, and the free video training was kind of like a cause for them.
If those videos are the same, they were a game changer for me in terms of gaining both a sufficient understanding of Bitcoin and comfort with having any involvement with it.
However, I waited a long time before having my first involvement with Bitcoin. It's funny because this thread reminded me I may have some BTC sitting in a wallet that I forgot about, perhaps a nice $xxx bit (pun intended). If it's still there then that may be only the second time I received Bitcoin. So to my knowledge I've had only two Bitcoin "episodes."
As far as using it for tithing goes, I see no point really, unless there are compelling and cost effective circumstances involved, which I imagine would tend to be extremely rare if not nonexistent. I also agree with the poster who wrote along the lines of how there is no requirement of tithing in the New Testament to begin with either, though one may want to do that or more, so I would just speak in terms of general "giving." I suppose the focus here is on regular, scheduled, automated, percent-oriented giving.
By now I would think there are numerous churches equipped to take online donations, including just using regular bank routing and account info, which I used recently even just to pay for a dinner event at a church, at least here in the US, so there seems no reason for any added step of converting to and from Bitcoin.
If you already have Bitcoin, however, then perhaps it may make sense to donate from it.
Furthermore, despite what I just wrote above I suspect it's probably a super great idea for churches and ministries to nonetheless enable donating by Bitcoin, which I would imagine some do already, and as far as I've seen would be super easy to implement, at least for single instance giving if not regular/automated.