A weak peso may encourage more investments (lower cost) that can help boost up further the BPO industry. OFW remittances would also have more value. This increases consumption which is favorable for a consumption-driven economy.
However, it can also increase costs as oil prices are in USD. Hence, inflation eventually follows.
Weak peso can have a net positive effect on the middle to upper class. Unfortunately, the poor severely gets impacted from it, and as we see, devaluation of peso is on its uptrend.