I don't believe the main competitors to Firefox (Chrome, Edge, Safari) offer a payment mechanism? So this wouldn't be required for core feature parity.

However the two main competitors to Signal (Telegram and Whatsapp imo) do have a payment mechanism.

I had no idea WhatsApp and Telegram have cryptocurrency support, I only use WhatsApp because I need it for soem school parents group though... but even if Chrome would add Gopogle Coin support I still will not like if Firefox forces it and not make it an optional plugin (people still complain that Firefox added DRM support for media so this is not theoretical)

Neither Telegram nor Whatsapp have crypto support. Both of them have very limited payments support, that doesn't use crypto at all.

Do Telegram have that now? I actively use Telegram but can't remember having seen it - nor an announcement that it is available.

Telegram has bot payments API (had it for some time now).

As a user (regular or a business owner for example) you can use solutions like https://ecommpay.com/products/telegram-payments/ to receive payments

Chrome has the Payments API and the most recent betas have the Digital Goods API which allows Play Store billing.

Keeping up with the Joneses is rarely a good motivation