It would cost you more time and just pile up more things to track. Value your time more than their convenience, these users have plenty more time to exchange it to the staple BTC & Paypal cash.
But a possible workaround is to delegate handling of payments on these alt-coins. This way you can accept payments with amped up prices, by harboring the exchange fee into your pockets, without costing you your time.
And also, this way you're getting more cut from your currency exchange sections without damaging their consistent payments on stickies because 90% of their exchanges are from WU-PP-BTC and they wouldn't be hurt so much.
But still, outside HF. Business wise bruh, if you ever established this, it's all in your terms to see what this mini-monopoly could serve you in the long run.
Jash