I'm glad you made a video on this promising exchange! I'm not sure where you're getting the $4million volume figure though, you say it twice in the video and the second time at 7:25 you compared it to Bittrex so I'm assuming you mean 4mil volume for the Binance exchange and not the coin. On Coinmarketcap Binance shows a volume of 100-150M and Binance coin makes up about 40M of that (today anyways) and in your video we can see the OAX/ETH pair which was listed on Binance August 20 so the video was quite recently recorded too. And 100-150M is quite competitive with large exchanges such as Yunbi, Bitstamp, and BTCC which is why Binance is currently hovering around #15 in terms of trade volume for exchanges on Coinmarketcap (which is just amazing for an exchange that has been live for a little over a month).

Another thing: "they're definitely not trying to target classic top 10 crypto currencies right now because other exchanges will have more volume..." you're right in saying they seem to have a focus on Chinese coins (they're a Chinese exchange so that seems like a great strategy which has worked out quite well for them so far) but I believe they ARE also trying to capture significant marketshare of the top 10 cryptos as they have USDT pairs for BTC and ETH so far, as well as NEO/BTC and LTC/BTC pairs which make up 4 of the top 10 within the first monthish of operation. They can actually offer competitive prices on these coins compared to some of the big exchanges because of their business competencies like you said; they have big partnerships which provide a lot of liquidity on their platform.

Other thoughts: I think they will retain (or hopefully increase) trade volume once fees comes. In their white paper they say they have no plans to charge over 0.2% for trading fees, making them competitive with some of the largest of crypto exchanges like Poloniex or Bittrex. If the trade volume is so high because of 0 fees as you imply, it may continue to stay high since the max proposed fees are in line with much larger exchanges while also offering incredible performance and versatility right out of the gate (it works on a majority of mobile and desktop platforms already). For these reasons, I think the BNB coin has great potential as well: since the max proposed fee is 0.2% which is in line with other crypto exchanges, a discount on top of that is very enticing, especially on an exchange with this kind of trade volumes which keep prices of cryptos competitive with larger exchanges, but with less fees since BNB offers a fee discount. (And as you could infer, a discount on 0.2% matters a lot more to traders who trade higher volumes which may help Binance continue to increase its trade volume at such a high rate).

Temporarily, since there are no fees on Binance, there isn't currently a use for BNB that other coins can't offer (store of value) so it's value is purely speculative right now (I don't think this will be an issue long term, in fact I think once it does have a use case you will see more trading volume on BNB as there will be a better reason to speculate a higher future price of a useful coin as well as incentive to trade the coin for fee reduction). I'm also glad they're working on decentralizing their exchange which will probably allow them to offer even lower fees like BitShares but without the problem of liquidity which BitShares has (not to mention BitShares keeps the order book on the ledger which means editing it costs gas). Decentralization will obviously also help alleviate trust and security issues with exchanges that exist today. Note, though: many of the large exchanges are also working on building decentralized version of their exchanges (Bitfinex, for example, has announced this as "Ethfinex") so Binance is by no means special in planning for decentralization.

All in all, for many the reasons outline above, I bought in early and am quite bullish on BNB and plan to keep a significant chunk of my portfolio (~20%) in Binance for at least the next month and lighten/increase that chunk if prices move in the appropriate direction in the coming weeks.