Undoubtedly, they are convenient when purchasing something of value, an expensive TV or bicycle for example, in cases where paying in advance is out of the question
That sounds like the wrong reason to use it in most cases! Unless it's interest-free, you're almost always better off just waiting and saving up to make the purchase.
I only proceed to use installments when they offer an interest free option. I'm not willing to pay 10-15% surcharge just to get installments. Likewise, I'll rather wait and pay in advance. I've never used it to buy something I couldn't afford, and wasn't offered with interest-free payments. It's just not worth it.