I have never seen a player win 1 btc, if that really happens the person who gets it from the free money is very lucky, I often ignore it, I prefer to just play without thinking about any bonuses
The chances to get that is so low but that doesn't mean no one can win it.
Somehow its your decision not to avail the bonuses since I see lots of gamblers don't want to pay attention on other thing and just want to focus playing.
You will hardly hear of anyone who has recorded winning the top gift on the daily free spin, not just on BetFury, and this should be because that is how it is.
If the prize is 1 bitcoin and the free spin is $0.20, you can imagine that the odds will be less than 0.20/1,000,000, which is 0.00002%. the probability of getting 5 numbers right in the EuroMillions, just the numbers, without the stars, which means you wouldn't win much, is higher. And you will probably not know anyone in real life who has gotten them right. If the free spin is worth $1, it doesn't increase much either; it will even be less than 0.0001%.