For reference, this line was
added in 2015 by Cassiel Seraphim, who built the library of wiki pages for Incursions and EVE University's Incursion Community.
For Incursions, that line is pertinent, as Nightmares generally do not use afterburners in Incursions. Nightmares are used because of their sniping ability with ten effective turrets while only having to power four, and with enough mid slots to further improve application on top of the tracking bonus, or also fit a shield tank for shield communities. In Vanguard sites, they run noprop as moving isn't necessary there. For Assaults and HQs, they run MWD because they need to keep up with other MWD-fit ships in the fleet, and even with max skills and a Gist-X 100MN AB, it will be 160 m/s slower than a meta MWD with max skills (881 m/s vs. 1046 m/s). That gap will be larger with lower skills and bling, which has potential to be a pain when doing the dual 60km sprints of a TPPH (common HQ site). Cap issues of the MWD are mitigated through their limited use, cap buddying, and occasionally a Capacitor Power Relay (which both shield HQ communities, Warp To Me and New Galaxy Age, recommend in their fits).
Outside of Incursion fits though, I took a look at what's been dying on zKill, and I struggled to find fully fit ships that didn't have an afterburner fit on them. From fits for
solo PvP to
mainline fleets, PvP applications of the ship seem to universally make use of the afterburner bonus. What few missioning nightmares made their way onto the killboard didn't seem to forgo AB either. With the speed bonus, the afterburners use much less cap while still being reasonably fast for a battleship.
Since Incursions is the one use case where Nightmares can seemingly be expected to not have AB, I would recommend that the blurb be written specifically with them in mind. Something like this:
The afterburner speed bonus from Caldari Battleship enables Nightmares to be agile (for a battleship) with an afterburner, freeing up capacitor for its lasers and a local repairer if it has one. Afterburners are very popular for PvP fits because of this bonus. However, for select use cases such as Incursions, where Nightmares are either fit with no propulsion module or with a microwarpdrive, the ship can be used effectively even with Caldari Battleship at level 1.
I think that such a blurb sets the conditions that you can get away with not running AB on the Nightmare a bit better.
And to be honest, considering how much the ship fittings and pages could use some love, if we can get a dozen posts in a day about
one sentence, I think we can really focus that energy towards getting more ship and fitting pages more up to date beyond their circa-2014 baseline. I brought up
the VNI back when it was reworked in July 2019, but didn't garner any responses. I hope we can keep this activity up, and get those pages to where they ought to be.