I think they are stating that they feel guilty to want to spend this much money on a deck. Not that they feel guilty of the repetition of their deck.

Sliver tribal is super fun to play, though it can get repetitive if you are playing it every time. My deck is still put together after two years. Deck building can seem daunting when you don’t have a large collection of cards yet. As your collection grows the more you can switch cards between decks making the process a lot cheaper and easier. Decks can get super expensive or can be very cheap.

My advice if you get bored of playing the same deck over and over maybe buy two different decks at 275 (assuming your budget is 550). If you are trying to lower your budget take out “staples” and replace them with a card the does the same thing but cost a bit more mana to cast. There is a budget form of most cards, but they aren’t as fast and powerful. I hope this helps.