Even if UASF will create altcoin then be it.
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I will use BTC as store of value and UASF to play casinos, pay for stuff. Same time let original BTC be original BTC.
You don't have a clue. UASF won't split it's a softfork. Some stupid miners like jihad and BTU bovine can ragequit and create their altcoin BTU, but it will be just alt like LTC, no more
You seem to be just repeating things you've heard without understanding it.
It can definitely cause a split, and the soft fork label is misleading.
It is technically a soft fork because non upgrading nodes can ignore the segwit transaction formats and treat the ouputs as valid. However, because they cannot see the witness data (a fancy word for digital signatures), they have to simply always assume they are true ("anyone can spend"). That's fine if all of the miners are playing along and enforce that the segwit outputs can only be spent by the sender according to the witness data, but if some don't play along (even a minority), then the chains will diverge because those "anyone can spend" outputs will be spent (by anyone), and the UTXO set will be different. Hope that makes sense.