"is even useful" is a correct and usable phrase in written English.
It is typically used to emphasize that something is not just useful, but particularly or surprisingly useful. Example: "Despite my initial doubts, I found that the new textbook is even useful for more advanced students."
The zucca brings nourishment to the limited winter table, and is even useful when dry — you can use gourds for water, utensils, containers, even musical instruments".
Biologists do not agree on what the definition of life should be or whether it is even useful to have one.
But Putin's life doesn't depend on Madonna's statements, and the image of Russia as a European Iran, where courts make theological decisions, is even useful for Putin, who can now say to the west: look, this is a wild, religious country that can only be ruled by authoritarian methods.
The school of thought "now known as Dominionism," meanwhile, is so known primarily among its critics: Many of the people that writers like Diamond and others describe as "dominionists" would disavow the label, many definitions of dominionism conflate several very different Christian political theologies, and there's a lively debate about whether the term is even useful at all.
In this case, under a strict interpretation, this hypothesis has been refuted; yet under a modified interpretation that accommodates new findings into a "statistical TOL", this hypothesis still awaits refutation and is even useful.
Some books are even useful, like the football I use to get when the one I had been using simply needed replacement.
Perhaps my fancy degrees are even useful in these endeavors.
Right now, we're just seeing if it's even useful to users.
The thermometry techniques on the basis of geochemical data are even useful to identify the target of heat anomaly.
T2WIs are even useful in the evaluation of potential compressions of the optic chiasm and hypothalamus by the tumour [40].
