The advantage with Bitcoin Gold is that even small-scale and medium-scale miners can mine this coin, unlike the case with Bitcoin and Bitcoin Cash. Although it has fallen quite a bit since the forking, if you check the charts then it can be found that for the past 8-9 months, it has held on to its exchange rate (versus Bitcoin), which points towards a small but loyal user-base.
BTG is not a crypto-giant, unlike BTC or BCH. It is meant for a specific target group and it has the potential to grow within that specific boundary.
Bitcoin Gold is easier to mine with GPUs than BTC or BCH. Despite this, BTG doesn't seem to be a quite attractive option for the average Joe. People are looking into popular cryptocurrencies which are always rising in price. BTG has lost a great amount of its value becoming an almost worthless coin. There needs to be constant innovation, and development for Bitcoin Gold to be able to succeed in the future. But, the most important thing is that BTG needs to obtain the level of mainstream adoption as other prominent cryptocurrencies on the market (like Bitcoin and Ethereum).
Still though, as you've said, Bitcoin Gold is ideal for miners. Which means, that the cryptocurrency itself might remain alive for a long time. Other than that, it doesn't seem to have a future as a usable cryptocurrency for the world. Hopefully, the dev team would come up with great ideas in order to make the BTG blockchain one of the best cryptocurrencies available on the market. Just my thoughts
