I think it had been a better decision, if the mod takes care on this and gives you at least a little overlap between the expiration of the bounty and your suspension term.
I think she didn't take care on that because so is it going SE-wide.
However, it was far not the worst one. Having only some hundreds reps, you are thinking yet that 50 rep is a lot. But, if you had posted an answer every day while you are suspended, you could have collected easily that 50.
There are things far worse that. For example, imagine a mod saying that your comments are too hostile, and suspends you for a month. Ok, then you get back, write much lesser and much nicer comments. Then the mod suspends you for a year, saying that he understood it so, that you should absolutely no commenting. Such things are possible on the SE, you survived it quite easily.
If there is a suspension or a mod warning, you have also a chance to talk to a mod directly. It is a rare, and costly chance. Don't miss it! If you think you deserved it, accept the responsibility and get back. If not, try to convince him about your view, or explain him, what you did and why.
In your case, I had tried to explain the bounty problem to the mod. Having an ongoing bounty is surely not a reason to avoid a suspension, but having your first crime, and saying that the problem of the bounty would make the punishment much harsher as it was intended, might have been a strong argument for the mod to do something.
A reduction or an elimination of the suspension is nearly unheard on this way, but so you have the option to let him/her understand, what you did and why.
Don't worry on the downvote pressure and the many, quite antagonistic answers what you got here. The SE community is, unfortunately, not very friendly in many important matters, maybe an improvement of the community would be here very useful. Until it doesn't happen, the best what you can do: ignore it, and don't stop your activities. Exactly this is what the community needs.