It is usable online if everyone has the same tweak settings. Enables private leagues for special fantasy class racing. Who wouldn't want to race (place random favourite car class here) against your friends?
tweak can be used not to cheat, but for fun.
lets say LX6 with 800hp...my favorite! or BF1 with 1200hp....when you get a grip with that, original f1 becomes alot more friendly...
so...tweak isnt necessarily bad