True. Certain U.S. futures brokerages don't offer futures traded on international exchanges such as DAX or Nikkei 225. That is one advantage of Interactive Brokers.
If you have a portfolio margin, they allow you to trade 6x the RegT. But PM is only available to those with $110K or more, so I don't think it applies to the OP. But it's a nice perk for those with big accounts IMO.
Tradestation is 50 cents per micro trade. $1.50 for eminis. I like the speed and platform as well. Been with them for almost 5 years. https://www.tradestation.com/pricing/#et_pb_tab_1
we are talking about all in cost, you are referring to commission only. ts all in for emini is $2.90 per side.