It's maybe a little thing, but there is a huge difference between saying the MP accepts salary in BTC and he receives EUR and then buys BTC.
If the government was sending him bitcoins to pay his salary from its own wallet, I would agree, but this is not the case.
It's like any other citizen that buys BTC when he receives his monthly cheque and logs in to a website to click a "Buy" button.
Are there even any high-profile cases of people receiving salaries in Bitcoin directly? So far it all seemed like stunts to promote some exchanges and payment proxies.
Then again, we know that the dude won't probably be doing this if he's living paycheck to paycheck just like most of us here.
That's a good point, middle class and poor people can't afford to risk with Bitcoin's volatility when it comes to money that they are spending on a daily basis. A 20% slide in price might be "just a dip" for a wealthy person, but it could seriously screw someone who won't be able to meet their monthly bills.