I can only speak for myself but I used the bike glitch for about 5 or 600K, to get me over the hump to buy an Entity and mod it a bit.
But cmon now HNL, you know how we get down .
We do EVERYTHING- Land, Air, Water races, Golf, Tennis, Missions, Survival, Sell cars, kill people, etc...
Pretty much everybody that runs with us has put in work. You dont get those guns with low Rank.
Plus the bike glitch dont give you RP, just money. And money really dont mean alot in the GTA :O world.
Once they open it up where you can buy money, EVERYBODY is gonna be filthy rich.
Sure it can get you a nice whip, but without the RP people are just gonna dust you in the same whip with mods you dont have,
or kill you with guns that arent available to you, etc..
RP, JP, achievements and records(lowest race times, lowest golf round, best tennis round, best darts score) are more important than money in this game IMO.