Yet provides a disadvantage for those who stake the bankroll for a very long time, loyal users with standing investments for several months or even years (at least a disadvantage compared to the current system).

Different sites handle situations like transaction fees or investment commissions in different ways, I don't think there's a right or wrong here.
Likewise, users might prefer one way or the other.

Gladly, we're currently in a phase where there are many different trusted services to pick from,
so everyone can find something suited for them (one just has to think back to when MtGox was the only exchange and everyone had to use it).
On top of that, there's viable alternatives to Bitcoins rising transaction fees with Litecoin, Ethereum or similar options all available on CG.

And after all, Lightning is just around the corner, possibly instant deposits and withdrawals with close to no fees, an interesting time, to say the least.