The phrase "actually usable" is correct and usable in written English.
You can use it to emphasize that something is practical or functional in a real-world context.
Example: "After testing the software, I can confirm that it is actually usable for our needs."
Alternatives: "truly functional" or "genuinely practical".
But not all the chairs are actually usable; some, like the one shown here, are more conceptual.
THE Earth may be two-thirds water, but only about 1percentt of that water is actually usable for human consumption and agriculture.
As Lord Robertson, the NATO secretary general, explained to me, all of the NATO European members, plus Canada, have a combined total of 1.4 million soldiers on active duty -- but only 55,000 are actually "usable" for missions abroad.
"The best improvement to the system is called OneBusAway," she wrote, a program "that takes county transit data (transponders that transmit a bus's location when it reaches a stop) and makes it actually usable by riders by providing real-time, accurate estimates of how long a bus will take to arrive at your stop.
It will be actually usable.
It's another manual drag-n-drop operation, but it makes music phones actually usable.
Though technically still functional, it is doubtful that the facility would actually be usable in an emergency the plumbing, for instance, has not been overhauled in 40 years.
Makers of blood-testing equipment have taken to charging only if the device actually produces usable data.
It turned out what the Americans considered trash — generators, cables, air-conditioners, furniture — was actually perfectly usable and could be resold.
As seen in Figure 12, recommended applications are actually not usable for the users in some cases.
As Nicholas pointed out, Google TV actually less usable than something like Plex or XBMC.
