Actually, bronjuan...what the multi-tip gives you is some versatility in one spool to be able to fish a full floater and a variety of sinking tip lines. The clear tip for example is excellent for fishing emergers or damsel migrations in the shallow shoals. You can even fish chironomids "naked" if you need to fish deeper than 15' by using the type 6 sinking tip and adjust your leader length according to the depth of the water you're fishing...this avoids using a clunky indicator, and gets your fly down beyond 15' in a hurry.
BUT...this does not mean that you will never use a full sinking line again. For trolling for example, you will want a full sinking line as tension on a sinking tip, any sinking tip, will pull up the short sinking head and soon you will be near the surface again. In short, a full sinking line gives you a better horizontal presentation, while a sinking tip gives a better vertical presentation. I personally don't use a sinking tip much on the lakes, but reserve them more for the rivers. Stripping leeches also tends to work better on a sinking line.
If you are looking for strictly a stillwater setup, then I can suggest that two flylines will cover 99% of your bases...get two spools and fill one with a good quality full floating line, and the other with a good quality Uniform Sink (sometimes called Density Compensated) Type II or Type III flyline. The two flylines will cost slightly less than the RIO Versitip, be more suited to lake flyfishing, and you can use the extra $30 towards the extra spool that you're going to need. HTH.