A more recent poll (from 2 days ago) finds that 21% stated they would either definitely (4%) or probably (17%) vote for BSW.
It is definitely one of the most interesting developments in German politics and I think it will have a net benefit, if only bc of its authentic opposition to warhorny transatlanticism that otherwise owns German politics and media.
However I can't read this party yet honestly, the sentiment towards it in Germany is a remarkable ball of contradictions. My two cents as a German, when I read the (understandable) hopes that it could be a socialist party.
Although the central founder (SW) was a socialist in her youth, I can definitely not call it a socialist party, they themselves don't. And in the recent press conference regarding their founding they also explained why, while many members come from a leftist tradition, they don't call themselves "leftist" (its important to not that left/right have different connotations in every country), their explanation was along the lines that these words have lost their meaning to the German people.
They gathered some of the best politicians you can get from the German left, their recent recruitment of Fabio De Masi is something hopeful, whose stance against finance capital is one of the staunchest (he is a union/reform-socialist, I guess that's the best you can get in Germany..)
However in their public communication there is nothing Marxist. They carry bourgeoise ideals on their banner. Since the established parties currently increasingly turn towards authoritarian measures and crackdowns against leftist groups there might be a strategic benefit in it for leftist groups though.
Their perception is dominated by other factors since the media exclusively focusses on them:
In Germany the "culture war" is a bit different than in the US, however here their position is not super appealing. They call out a lack of legislation focussing on material conditions of workers, but they draw from the culture war that this necessitates opposition to socially progressive topics and adopt somewhat of a reactionary position in some of these regards. IIRC SW called herself socially conservative.
This is one of the reasons why the parts receives more hostility from the liberals that consider themselves of the left, the other is their stance on refugee policy. While some of their members have in the past advocated for open borders it is their official position that "the numbers need to be lower", their argument is not the ethnic-popular one that the media tries to put in their mouth but that integration-efforts are past its limits to which there is probably some truth to.
Their championing of bourgeoise values and the parts of their position to gender politics that are reactionary as well as their refugee policy seems to be much of the reason for their popularity. Partly bc the media focusses on these things exclusively (and on unfounded speculations they might be "in the Kremlins pocket"). But also no other German party wants peace in Ukraine and the Palestine and that appeals to people as well. They have some credibility bc they address truisms that are swept under the rug, like that the Nordstream bombing was facilitated by the US. The husband of the central founder was literally the only politician who would talk openly and frequently about the influence of US intelligence agencies.
All this will lead to a lot of member-applications from problematic corners os German society. They have announced that they will be careful with their admissions, and I see potential for growth in a "good" direction (probably not socialist tho).
While I see that they do and say some things bc it is necessary in our political landscape and having a traditional socialist party is impossible in Germany, I can't bring myself to see them as Socialists with a practical strategy, but they are also not Nazbols. Currently (I didn't dive into it) I believe they represent a true demsoc approach and flirt with that part of the national bourgeoisie that stands to lose a lot from transatlanticism, like companies who deal with Russia and China.
I believe strategic support is the right way currently, but I doubt they can be swayed towards a Socialist evolution. How they develop will be greatly influenced by how they will deal with the incentives they operate in, like capital interests and the media stirred excitement of reactionary elements for them.
Didn't wanna cloud anyone's enthusiasm, they are good news, especially with the AfD turning more and more radical on the right AND having more and more success in the polls.