I'm not a believer of small bets before since I'm very lazy to gamble using small amount because I think that can't make real profit out of it before.
I experienced this first hand yesterday when I lose my 500$ bankroll after an 8hrs of Blackjack session. I was so down that time and just claiming my bonus rakeback before I leave the casino. I bet it on a ladder game by turbo games provider which is like a mines game. To make it short, My 4$ bonus that I collected on my rakeback turns into 600$ buy placing bet on this game and manage to win multiple high multiplier since I don't feel any fear that time on my bet.
I recover my loss and manage to win some profit. A really bad games turns into comback game with just a 4$ bonus from my losses.
The end of the story is very nice because you can take back what you have lost along with profits and this is done only by using bonus capital with a very small value, you have to be really confident when betting with large betting values, while the capital used is not big.
Usually I will always choose the smallest bet because I hope to play longer and wait for luck to happen, but you are right when a player only bets a small value when hit a high multiplier that does not provide significant profit to the player, so sometimes it is necessary to be brave to bet with a bigger value than what players usually do and when players can get a high multiplier the profit is really very big and the opportunity to replace what you lost opens up, and it takes courage to also lose money faster because you don't reach the desired multiplier.