It depends on how you look at it. A phase out of UBI could also be viewed as an additional tax.

In fact, you could consider the current system of benefits only if you are not working a form of UBI, if you just treat the UBI not received by the working as a tax against the benefits they would have received.

All in all, UBI isn't much of a departure to what we already have, except that people are expecting the benefits given would be much moar.