They are simply trying to popularize their app and are rewarding you for helping them, real games (for money) or participate in tournaments. If you are using basic strategy, the rules determine the house edge. Table games contribute 10% or less, so check each promo's terms.
https://my-mobile.eu/viewtopic.php?t=8082
http://horsecity.ru/phpBB3/viewtopic.php?f=25&t=449757
https://foro.murenacidos.com/showthread.php?tid=12826
http://forexam.ru/component/kunena/?func=view&catid=5&id=161428#161428
https://muchroom.ng/index.php?topic=70297.new#new
https://www.ww2.site/forum/viewtopic.php?t=46924
http://horsecity.ru/phpBB3/viewtopic.php?f=33&t=131432
https://talkingpoints.org/subx/showthread.php?tid=114452
http://oldsite.giessen46ers.de/fantalk/viewtopic.php?f=3&t=260397
https://catrachosporelmundo.com/index.php?topic=16323.new#new
https://my-mobile.eu/viewtopic.php?t=17356
https://www.ww2.site/forum/viewtopic.php?t=399511
https://www.ww2.site/forum/viewtopic.php?t=342141
https://democratstoughlove.com/showthread.php?tid=29357
https://boards.streamweaver.app/showthread.php?tid=8573
http://1.s.2.free.fr/viewtopic.php?f=13&t=661260
https://www.ww2.site/forum/viewtopic.php?t=100748
https://catrachosporelmundo.com/index.php?topic=8613.new#new