On top of this the market is crazy volatile so we don’t even need to go that way. Definitely no need to go for premium services as we will end up loosing more than we can earn.
It depends on what market you are talking about. Altcoin markets are always volatile because they are pump an dumps. But bitcoin is stable a lot of the times and the big changes in short term are becoming rarer. For example over the past 24 hours price has only changed 3%.
Additionally when we are talking about arbitrage trading this way, the trade doesn't take that long and if it is between two peers then they can still come up with an agreement over the exchange rate then commence the trade.