There is newer a guarantee of NOT getting banned, there is always a chance when using 3rd party software, as its against blizzards TOS. There have been banwaves in the past but HR have survived yet.
Furthermore even if blizzard doesn't find this bot through automation or within code of hearthstone or battlenet, there is a chance people reporting you.
I think its safer using casual games than ranked.
Furthermore don't overdo botting, don't let the bot play straight 24/7, don't bot at unusual times. Example is playing all night in your time zone. Use decks that the bot actually can play accordingly with cards it know and can handle great. You don't need 70-90% winning rate if its for getting gold, 50% is alright.
I have better experience with yoin's deckrules and don't use silverfish as in the past it had some issues but I believe most are solved yet.
I also use ranger crash recovery made by a member here to also have some waiting time between games and it handles crashes quite well.