The 66 circuits fill both rows fully — every position is loaded — so the BOM line is a straight count match for a 66-conductor ribbon cable or a dual-row receptacle.
That 5 A figure is typical for a signal-level header at this pitch — it'll carry logic-level power or low-current I/O, but don't plan on running a motor feed through it. The tin plating is fine for a one-time mate in a permanent assembly; if the board needs to be disconnected and reconnected more than a handful of times, the tin will wear and contact resistance will climb. The 0.100" (2.54mm) insulation height keeps the pin field low-profile above the board surface, and the 0.120" (3.05mm) solder tail length is sized for a standard 0.062" PCB — no special drill depth needed.
No last-time-buy or end-of-life notice to plan around.