When I got my free bet (for matchday 2) it was just a credit, with no requirements at all. I still wagered it at as I thought it would not be fair just to withdraw it straight away, as it was meant to be a free bet, but there were no requirements whatsoever.
I'm not sure if anything changed since then, or if maybe others are referring to something maybe mentioned in the Terms of Service, which doesn't necessarily relate to the $50 free bets for this competition? I don't know.
Well, your freebet was rewarded far before Vega.bet announced news regarding the way freebets are credited. cygan posted it few days ago:
@all there's news from Vega.bet regarding the 50 USDT free bets.
until now, the 50 USDT has always been credited as pure balance to the matchday winners, and if a bet won, Vega.bet did not withhold any amount.
now the platform is finally switching to the free bet format, and effective immediately, if a bet wins, the amount of the free bet will be deducted from the total winnings (as is standard practice at all another bookies)
It makes sense because Vega was basically giving away free money by crediting those $50 as a deposit. This way (with a standard freebet reward) they keep that $50 in case of a winning bet, and the player gets only the earned part. For example if you win a ticket with 1.50 odds, you only get $25 credited to your account. The reward itself is kept by the bookie. That's the way how other bookies are doing it.