Perhaps lead by example. 1YAXCNpdeEBBBdzPqBqTEhT6e9czV5Y5f, your Jetwin payment address is neither nested Segwit or bech32.
I don't understand it either. Why some people prefer their "amazing" and "unique" vanity address over SegWit address which is cheaper in use? The latest Electrum allows generation of native SegWit addresses (bech32) so why shouldn't we force campaign participants to use them? Even some exchanges started to support SegWit deposits. It's surprising that many people still don't know about SegWit.
Because not everyone wants to use Electrum. Some might prefer to keep their funds on a phone, some might have a cold storage address that they don't want to regenerate so that it's bech32, and some might want to sell off their Bitcoin once they get paid directly. There's no point requiring bech32. Also, I believe all exchanges support SegWit addresses, given that the nested version is backwards compatible and all exchanges should support multisig, and bech32 *should* work unless the exchange has some really weird custom wallet. In the ChipMixer campaign I manage, out of over 50 users, only one is getting payments to bech32.
It's also possible to generate "amazing and unique" bech32 vanity addresses (user
nullius has 3NULL3ZCUXr7RDLxXeLPDMZDZYxuaYkCnG as a nested SegWit address and bc1qcash96s5jqppzsp8hy8swkggf7f6agex98an7h as a bech32 vanity.