Yes, I understand the rudiments of midi and have been using it with biab for years. But some of the midi instruments, especially the horns, aren't very good. But you answered my question. Thanks.
Some of the midi instrument sound libraries available are indeed, not very good.
But some are much better. Some are actually worth spending money on
Spitfire has some great orchestral horns.
Native Instruments also offers some good horn stuff.
But neither of these are free (although Spitfire did have a freebie a couple years ago).
In general Midi instrument voice quality is much (MUCH) better than it used to be.
For my $.02 It remains a bit of a "you get what you pay for".
Also you can't play a trumpet like a guitar.
Or vice versa.
For midi instruments to sound compelling, you have to play as if you understand the instrument voice you are using.
I'm sure there are bargains. I just don't know much about them.
As I age I'm more willing to pony up the $$ and buy the quality stuff.