Depends on how botters use their cheated ranks, if they keep to themselves and rarely spend gil the impact as an individual botter is almost no consequence given the huge amount of obtainable gil straight from the environment. However take 100-200 bots that is a significant impact.

In the case of a fish bot, where they are most likely mass producing crystals to their ends. If they straight up sell every crystal they make because they dont craft, that has a huge impact on how much gil exchanges between players, this is making the most of being a cheater.

On the other hand a fish bot that keeps all their fish and crystals to use for their own crafting. Has a reduced impact on the way ffxiv exchanges work. However having an abundant source of crystals allows them to craft with one less supply restriction, allowing for more ranks faster. When there are more high ranked crafters, prices of goods generally go down. However we only see price drops on highly sought after items such as "final pieces" while rank 10-39 gear prices is higher than ever before (this is the problem with itemization with almost no level restrictions which is a whole different topic).

One could say the only way the relationship between crafters and combat classes is favorable because of botters. While it is depressing on an individual level, on the grand scale, "final piece" goods are only this cheap and in huge supply because of the effort of crafting bots and fish bots.

However bots are bad and must be purified with Ifrit's flame.