I used to ask the same question when I saw these kinds of promotions before 😄
Well, a 100% match on your first deposit (up to 1 BTC) means that Vave Casino & Sportsbook will double your first deposit in bonus funds, but only up to a maximum of 1 BTC. For example, if you deposit 1.5 BTC, Vave will still give you 1 BTC as a welcome bonus for the sports bonus.
On the other hand, if you choose the casino welcome bonus, you can get up to 4 BTC...