Have you ever won a significant amount using a bonus?

Yes. Often. Both deposit and no deposit bonuses. A no deposit bonus will usually come with a maximum withdrawal limit and a deposit bonus will usually not have a maximum withdrawal limit (except for the daily/weekly withdrawal limit). You can obviously search the CHIPY main bonus blog for a suitable bonus or ask in your casino customer support. Good luck. 

I have won on many occasions. The no deposit bonuses  do not allow for a jackpot hit, although the amount one can win varies with each site. There have been times when I have won several thousand and after the playthrough hits they take almost all of the winnings back. But there are several gaming platforms that have allowed the credit to be kept and spent on any game that one sees fit but when It comes to cash out, mostly they don't let you withdraw any cash. Hope this helps and good luck