The 8 mA source and sink rating is typical for 5V CMOS bus transceivers. It can drive up to eight LSTTL loads or a handful of CMOS inputs on a short backplane trace. If your load requires more than 8 mA per line — say, driving an LED indicator or a relay coil — you will need a buffer or a higher-drive part like the SN74ABT2245DW (32 mA per channel). For pure logic-level translation between 5V domains, the 8 mA is sufficient and keeps the package cool.
Through-hole package – board integration note
The through-hole mounting means you can hand-solder it without a reflow oven, and it is easier to probe during debug.