I was thinking about this earlier this morning after watching a YouTube video about the fork. Right now I don't think it poses a problem but it is a slippery slope for BTC. If I am correct, I believe I heard some rumors that BTC might have some other form of BIP whatever the hell number you want to attach to it this time in September/October.
If they go about another update in that time or even withing next the year, it will mean a couple things IMO.
First thing would be that the initial Bip 91, which implements BTC Segwit2x is having a lot of performance issues/bugs/security vulnerabilities etc.
The second thing is that BTC Cash is going to be booming as people begin to shift using that as their main source of currency for the the crypto world. It technically is the coin that original BTC would have been after the fork if they went with bip 148. So that right there is one argument as to why people would begin shifting their funds. Also from my research BTC Cash has some very influential backers of the coin, who want to see this coin succeed and take over BTC.
So if it happens again it would be for either of those two reasons I mentioned or both reasons. And if they decide to do another update they might as well fork the damn thing, because the BTC community that was mostly against reached the agreement of the soft fork of Bip 91 which IMO has cause more confusion in the market. Or...as some positive minded people would say "opportunity" to get in on BTC Cash while it is still really cheap if it over takes BTC as the main crypto currency.
I think the Alts will be safe regardless because they have millions/billions of dollars in BTC they also will have received the same amount of BTC Cash. So the only thing I would like to know is what companies decided to sell their BTC Cash, Didn't even attempt to get it, and Kept it?