Mostly as a precaution as it hadn't been adequately tested. It's enabled in master now and has been for a long time... running master should be a no brainer.
I'm really interested in adding a pruned node to my
Tails + JoinMarket scripts for users. I think it is very important, especially now that Tails comes bundled with Electrum 1.9.8, which is obsolete. End users are having a horrible time trying to install newer version of Electrum, mostly because of the amnesiac properties of Tails.
Anyway, it would be very powerful for Tails end users to have a node at their disposal using only ~2GB of space. Right now most Tails + JoinMarket users are using the blockr.io api call for address balance/confirmations because they tend to not have a usb stick large enough to store a traditional unindexed node, and this is terrible for security even though it's over Tor (address correlation, etc.). If I could offer a small size Bitcoin Core node for Tails users... well you get it.
So I guess my questions are:
1. Do you think it's too early to offer to users as an option? Even with a strict warning?
2. Would it be a horrible idea to offer weekly updated downloads of the pruned chain? I could host them on github, and users can curl them over https. Also I could sign them and users can verify. My reasoning on this is bootstrapping the client is going to be my next hurdle in getting this adopted.