They are good for high current and high voltage, yes, but that is intended to be in brief intermittent pulses, not audio. Look down the data sheet to Safe Operating Area. Note the part can be used at various cuurents and voltages, but the curve tells you how to use both together. The curve of interest is the one marked DC. The part is OK with 5 amps current, but only up to about 15v. By the time you get up to 50v, the allowed current is down to 0.7 amp. And at 100v, it is only half of that much even. Looking further, you CAN draw 10A through the part at 100v, but you can only do it for 50 microseconds.
The venerable TIP41C and TIP42C are 6A 100v parts, NPN and PNP respectively, and Allied currently lists them at 60 cents and 44 cents each. Need higher voltage for drivers? Try these from Allied:
MJE15030 NPN 8A 150V 94 cents
MJE15031 PNP 8A 150V 94 cents
or a bit more voltage:
MJE15032/33 NPN/PNP 8A 250v about $1.05 each
Those are US types, Asian numbers like these are used as drivers in comercial gear:
(Prices are from MCM)
2SA1306 PNP 160v 1.5A $1.70
2SC3298 NPN 160v 1.5A $2.29
2SA1011 PNP 180v 1.5A $0.62
2SC2344 NPN 180v 1.5A $1.23
I don't know how ceap you are finding these parts, but I think real audio parts are not overly expensive. Cetrtainly there are others than those I mentioned, I just spotted those in my parts drawers.
Having said that, you might get away with it in your application.