You'll want to ask this question in the altcoin mining section.
That being said, it probably wouldn't hurt to do some ETH mining and convert to BTC with your setup if heat isn't an issue. Just make sure your fan profile is set aggressively and underclocking is your friend as mining is intense and most hardware needs default adjustments to keep from turning into a paperweight over time.
Could you explain more on why you state ETH mining over all the others? im trying to learn more about the details on why people choose specific coins to mine, from my briefing understandings, some miners are more efficient on GPUs over others.. and even different on AMD vs Nvidia...