because this is more of an investment and people put their money there to make a profit.
I agree that people buy cryptocurrency for investment, but do not forget that many people buy and store savings in stablecoins instead of fiat currencies, so the opportunity to pay with stablecoins will be very useful.
stablecoin is more appropriate for paying since merchants will prefer it to tokens because they know the value could change at any minute. even in the bull market, those who are trying to make money outside crypto market are going to prefer stablecoins. the issue they could only see is the transaction fee as sometimes it could be way above what they expect.
i tried looking into the $IVPAY, coingecko page has a warning about the project that migrated to another contract address. most projects i know that migrated its token to a new contract died. i could be wrong but this is what happened to them.