Let me be a little more specific: as TBI systems go, the Holley ProJection system was junk. The GM system was markedly better. And if you really don't understand why people are even interested, then you probably have the luxury of enough spare time and money that you don't have to understand. I agree with what seems to be your philosophical standpoint, that a job worth doing is worth doing right. But a junkyard TBI swap is vastly easier, faster, and cheaper than any kind of port fuel injection retrofit, and while the end result isn't as good as port fuel injection, it's still enough better than a carburetor to be a very cost-effective option to consider for those unable or unwilling to spare the time and money to do a port fuel injection swap.
