So right now on average the daily payout for Siacoin is $9/day so shows the following link
https://www.asicminervalue.com/miners/bitmain/antminer-a3-815gh
the current price of Siacoin is about .01
https://coinmarketcap.com/currencies/siacoin/
secondary calculations
https://cryptorival.com/calcs/siacoin/#result
Speculations made from Altcoin forums
--most users report getting anywhere 1300-1800 Siacoins daily ---
If this is true then ((1300*.01).......(1600*.01)) it may still be profitable over the course of the next 6 months.
[1300* 30days= 39000 & 1600*30days=48000]
If you get anywhere from $13-16 daily and convert it to BTC and trade out of it then you could have a worthwhile investment.
13*30= $390 & 16*30=$480
However it all depends how much you spent on the A3. I for example spent about $1800 so I think it'll pay off sooner than later.
Even with GPU's my point is to get paid and trade through BTC to another formidable ALT coin or just take the cash and run.
I suspect this isn't a "Door Stop 2.0" not for at least a 12 months.