"Thus" vs. "Thusly"

I read an article that used "thusly" and was wondering if there is any grammatical credence to it.

The quote:

The issue started when Sokolowski quickly ran out of storage capacity in his 32GB Surface after adding media files. After poking around, he realized that while the device has a 32GB drive, only 16GB of that capacity is available for users’ data. Thusly Microsoft is being sued for false advertisement, with the suit seeking class action status.

Is thusly an outmoded form of thus, or does it have a different meaning altogether?

The Oxford English Dictionary records thusly as a colloquial form of thus, with an earliest citation of 1865. However, it is really quite unusual, and I wouldn’t recommend its use other than for some kind of special effect.

Other answers have aimed at the redundancy of thusly, but I want to highlight its usefulness.

Thus has two senses: "as a result or consequence of this; therefore" and "in the manner now being indicated or exemplified; in this way". But thusly can only be used in the second sense. Thus thusly is useful when the writer wants to avoid confusion between the two senses of thus.

For example:

Because the treatment was said to be efficacious, and thus reported by the national press, many were persuaded to try it.

Was it reported by the press because it was said to be efficacious, or was it reported as efficacious?

Certainly there are other ways to disambiguate the meaning (we could say "reported as such", etc.) but thusly is so economical. Why should it not be used?