If you collect them they are worth it and if you sell them to another collector it's worth it. If you intend to sell them to a coin shop or something most place's are going to consider them bullion and give you melt for the proof's so it won't be worth the additional cost. To them it's just another silver coin although there is some better pricing on better dates. For the most part though proofs are a losing proposition unless you just like them then I'd say spend your money however you want to and don't worry about what it would sell for.
Yes they are worth the price, if you buy them several years after they were released and their price has dropped down to a reasonable market price. And even then their value will be closely tied to whatever the bullion value is.
Depends how much you pay for it Depends in the future if/when you sell it if you accept the price dependent upon how/where you want to sell it. If you are buying it for an investment because it's a "proof" then it completely depends upon which year you are talking about, how long your hold it (can't tell the future), and what you can sell it for (can't tell the future). In general, if you sell it in a down economy and/or where there are few buyers, expect a low price. Conversely too.
