Because the entrance leads to a plaza south of Atlantic Avenue, it saves those going to the Atlantic Avenue-Barclays Center station from crossing Atlantic and entering at the congested area connected to the Atlantic Terminal mall.
The arena is billed as being linked directly to nine subway lines, but as I explained earlier this week, it's effective really only for six lines: 2/3/4/5/Q/B.
(Those going to the D/N/R at (formerly) Pacific Street must travel up and down underground--useful during bad weather but indirect otherwise. As Benjamin Kabak of Second Avenue Sagas put it, "Via passageway, staircase, platform and another passageway and staircase.")
Also, as I experienced yesterday, the new configuration makes it far easier transfer between the 2/3/4/5 and the Q/B. Take a look at the schematic below. The Q/B platform is at right, the 2/3/4/5 at left. The two clusters of tracks converge at the southern end of the Atlantic Avenue station, near the arena entrance.
|Schematic from Final EISl Q/B tracks at right; 2/3/4/5 at left|
Kabak mentioned this earlier:
In fact, this station could improve the transfer between the IRT and BMT as the walk from the back of the local 2 or 3 platform to the lower level BMT Brighton platform is much shorter.It also should make it easier for Q/B riders to get to the Long Island Rail Road, since they could get out at the south end of the track, go to the northbound 2/3 platform and walk to the LIRR.