That wasn't the case at least for me.
I couldn't ignore the decentralized part of the deal, because I couldn't register at mastodon.social like how I could with twitter.com. Registrations were disabled (still the same as of today) and I was told to find a server.
I guess most people would give up at that point, though I still gave their server browser a try, and couldn't find anything that looks remotely official on the first page. It seems every Mastodon instance is its own kingdom managed by people I don't know running on arbitrary rules they've set. I could build my kingdom, but of course I won't, since I wasn't interested in the decentralized bit anyway.
tl;dr for now mastodon doesn't offer an easy path to just use the service w/o thinking about its details.