The problem with incendiaries on bots is that there really is no way to keep them fair and interesting on bots. There really does seem no way to balance their use by bots and get them to some sort of interesting place.
The problem is that an incendiary is designed to pretty much immediately kill anyone within their area of effect; no fuse, no warning, just immediate death.
What this means is that no matter how inaccurate a bots throwing is, if they so much as land an incendiary close to a player, that player will die with no actual chance of doing anything to prevent that death. And one can not make bots too inaccurate, since that throwing is necessary to allow the bots to throw any other grenade with any semblance of usefulness.
Combine this with the propensity of the the AI to literally inundate areas in grenades and you have a recipe for a weapon that is imbalanced and unfun by design and toxic to the gameplay in general so long as it exists in the hands of bots.