It has following consequences.
1. Even if you have unlimited free SMS you have to pay for MMS(As it is converted to MMS)
2. People replying using the 'reply' button on their non-Android phones can, without realising, send their replies by MMS, and hence cost themselves more money than necessary.
3. A lot of people's phones cannot accept MMS messages, whether that be due to hardware limitations or that they are simply not set up for them
If you have any suggestions(good/bad), feature request or Bug Report for Long SMS then please send same on [email protected]