I think you answered you own question? Hence the curiosity about how a buggy with a different body and tyres is going to be more fun than a buggy.
In the past I've watched people switch formula in order to 'win', or buy another car so they can get more races per club meeting. Both of these approaches increased the enjoyment they were getting out of racing so no problem there. The only worry is that it might reduce the ability of new drivers to improve as graded heats and finals disappear to be replaced by a single heat of 2WD, one of 4WD, one of 18th, one of SCT etc.