I used to think so because TBT is worth so much in game bells now but in reality, you spend lots of time on the forum selling items, art or even posting. After all that effort, you've earned them in my eyes.
I don't feel it's cheating, it's still work you put into it so I mean, you earned the TBT so why not? And also people TT and "cheat" in other ways to get perfect towns, or lots of bells. So why would it matter? There's always more than one way to play a game and I don't think that necessarily denotes cheating. I paid off my first house by catching beetles. But now I sold a chunk of my TBT so I can finish all my non mayor houses!
I also notice that having more IGB just really opens the game up in a different way. While there's no struggle for earning money I have different things I care about that don't really ruin the game for me. I worried about it doing that, though. But really it's your call in the end
I think it's kind of akin to using "motherlode" on Sims, yeah it's technically a "cheat" but after buying your dream plot you need something to buy furniture with. Am I right?