Any levels past 50 can be counted as bonus, yes, but not if you want to be competitive. Level 50 is indeed a softcap, but only -because- the levels after it take so long to achieve. For casual players that don't want to be competitive in the game, yes, it doesn't really matter much. Not trying to be a downer or anything, that's just how the game is. Personally, I find that ok. Casual players shouldn't be as strong as competitive ones that put in way more work.
Edit: It's kinda similar with gear. +15 is the base that pretty much anyone can achieve and most players will have, but after +15 is where the gears really gain a huge boost. The people that grind more/are luckier with RNG will be far above everyone else, the closer they get to +20(max). Gear, however, seems to get a bigger boost, and even harder to achieve as well. This is actually the thing that might prevent me from getting too into the game. I will probably love it until RNGesus brings his wrath upon me.
I am praying that this community will value skill, and that there will be regular player-made or GM pvp events where gear is equalized. That would be very fun for everyone in my opinion. I think how this game will turn out depends on how the community turns out, which can be good or bad depending on how you look at it.