After its invention, an aggressive marketing campaign was initiated to sell them with slogans like "Protect yourself!" advertising its use to defend oneself from bandits and brigands. It became so popular that ironically most bandits could be counted on to have one as well, which fuelled further sales. One can only assume that Gabriel died quite wealthy (or given Sapkowski's sense of humour, a victim of his own invention!).
In the game, the Professor uses a miniature wrist-mounted crossbow, which is more than likely one of these weapons.