No. By converting the data to a full Voice you can now take advantage of all the normal Voice parameters.

When you sample audio to the XF using the Integrated Sampling Sequencer, the audio is placed in a "USER SAMPLE VOICE". Audio is not recorded to a track, in reality. It it placed into a very basic Voice, the "User Sample Voice" and assigned a KEY (C-2 ~ G8). It is simply a place to house the sample. It does not have all the features of a full XF Voice. This is different from a normal User, a Mixing Voice or Preset Voice. The "User Sample Voice" does not have envelope generators, or filters, or sophisticated pitch, timbre, and loudness control, it doesn't have its own EQ per sample, it's own routing to Insert Effects, etc. It simply holds the sample so you can trigger it for playback.

By Converting a User Sample Voice to a full Voice, you can now take advantage of the full power of the programming features of the XF Voice architecture... Full set of Voice Edit parameters.

When you intially sample audio to the ISS, you can sample through the Insert Effects of the XF. But your data is simply placed in the very basic User Sample Voice location (and is given the Bank ID of "Sp:xxx" where xxx is a number indicating the order of your sample session in this Song or Pattern). When you Convert you will have moved the data to the "MIXING VOICE" Bank (MV:01 ~ MV16) one of sixteen full VOICE locations associated with the current Song or Pattern. It is a "full" Voice, with envelopes, Filters, amplifier, EQ, tuning, controller assignments, etc., etc.

When you CONVERT to Voice you have an option to create a MIXING VOICE (which can also then be stored to a regular User 1-4 location)... A regular USER VOICE: USR1, USR2, USR3, or USR4.

The big difference between the Voice before conversion and after is that the complete set of XF VOICE parameter tools are now available.

Often a raw sample recording doesn't "pop" like the internal instrument sounds. This is due to the internal samples have been "dressed up" with all of the XF's Voice parameters. Converting your recording to a "full" Voice allows you to "dress up" your audio sample same as Yamaha programmers dressed up samples in the permanent Wave ROM.

Before CONVERT, the audio is "as recorded".
After CONVERT, the audio has access to the magic of the Motif XF Voice engine.

Hope that helps.