tmiw: There's no use for the Pesos remaining as Pesos unless you plan to pay someone via Paypal in Pesos later.

But if you might have and there's no urgency, don't do the conversion now, you can always do it later.

I have a similar balance in USD (my primary balance in HKD) - a separate Paypal account in fact - but there's plenty of payments I can make in USD.